The dim glow of a single lamp cast long shadows across the cluttered living room, where the air hung thick with the scent of old carpet and sweat. Mark's knees dug into the rough fibers as a sudden, grinding ache bloomed at the base of his spine, radiating outward like fire beneath his skin. His fingers clawed at the floorboards, nails scraping audibly, while a low whimper escaped his throat unbidden. Derek stood a few feet away, arms crossed, his eyes glinting with malicious delight as he watched the first subtle shifts ripple beneath Mark's shirt.

"Look at you already twitching like that," Derek sneered, his voice low and mocking. "All those stories you obsessed over, the movies where people begged for this kind of thing, and now it's happening. Pathetic. Does it hurt yet, or is that little thrill keeping you on your knees?"

Mark's ears burned, the cartilage inside them stretching with a wet pop that made him gasp. He could feel them elongating, the tips sharpening into unnatural points that brushed against his hair. The pain was intimate and relentless, twisting through muscle and bone, yet beneath it pulsed an unwanted heat in his gut, the same shameful fascination that had drawn him to transformation tales for years. He shifted, hesitant to stand, knowing the door was right there but the sight of him—ears already wrong, back hunched—would draw stares or worse if anyone else appeared.

Derek circled closer, boots thudding softly. "Go on, run if you want. But imagine the looks. A grown man sprouting dog ears in the hallway? They'd laugh before they even called for help." He chuckled, the sound sharp and cutting. Mark's breath hitched as a fresh wave of pressure built at his tailbone, a nub forming, pushing outward with agonizing slowness. His cock stirred against his jeans despite the horror, the conflicting sensations making his face flush hot with humiliation.

Sweat beaded on his forehead, trickling down his temples as his shoulders began to ache, bones grinding inward. The room's silence amplified every sound: the creak of his joints, Derek's steady breathing, the faint whimper that kept escaping his lips. Mark's hands trembled, palms slick, and he pressed them harder to the floor to steady himself, refusing to meet the other man's gaze.

"You're getting off on it, aren't you?" Derek continued, voice dripping with contempt. "That fetish of yours turning real, even as it breaks you apart. Slow, just like you always described in those fantasies. Feel it yet—the way your spine's pulling, reshaping?" Another stab of pain confirmed it, his lower back arching as the nub lengthened further, straining the fabric of his pants. Mark bit his lip, the taste of copper flooding his mouth, his mind a tangle of dread and that persistent, unwanted arousal that kept him rooted in place.

Mark's breath hitched sharper as the pressure at his tailbone intensified, the nub swelling thicker and longer with wet, grinding pops that sent jolts straight through his pelvis and into his swelling cock. Derek's boots stopped right behind him, and then warm fingers were sliding under the hem of his shirt, tracing the shifting knobs of his spine before dipping lower to palm the emerging tail base through his straining pants. "Fuck, it's really coming in," Derek muttered, his voice thick with something hotter than mockery now, squeezing the sensitive protrusion hard enough to make Mark's hips buck involuntarily.

"Oh god, no—my body's changing, I can feel it twisting me into something else!" Mark blurted out in a shaky rush, the cliche tumbling from his lips like a rehearsed script even as his cock throbbed harder against the denim, leaking a sticky spot that Derek's other hand immediately found and rubbed over. The touch was firm and deliberate, cupping the rigid length and stroking along its underside with slow, deliberate pressure that made Mark's thighs quiver. Sweat slicked his skin everywhere, the room's thick air carrying the musky scent of his own arousal mixing with Derek's cologne as those fingers worked him through the fabric, squeezing the head until pre-cum oozed freely.

Derek chuckled low, tugging Mark's zipper down with a rasp that echoed in the quiet room, freeing his aching cock to spring out heavy and flushed. The hand wrapped around it instantly, thumb smearing the slick fluid over the crown in lazy circles while the other kept kneading the lengthening tail, now pushing out six inches and twitching with every stroke. "That's it, keep talking like those stories you love," Derek said, voice husky, pumping Mark's shaft from root to tip in a rhythm that matched the tail's growth—each tug making the new appendage stretch further, the skin stretching taut and sensitive. Mark's ears flicked, the pointed tips brushing his hair as another wave of heat flooded his gut, his balls tightening visibly under the attention.

"Please, Derek, not there—don't touch my tail like that, it's too much!" Mark gasped out another line, voice cracking with genuine overwhelm even as his hips pushed back into the fondling, craving more friction on the throbbing nub that was now curling upward, fur starting to prickle along its length. The cock in Derek's grip pulsed hot and hard, veins standing out as the strokes grew firmer, sliding the foreskin back to expose the glistening head fully. Sensory overload hit hard: the wet sound of the handjob filling the air alongside Mark's ragged moans, the salty tang of sweat on his tongue from biting his lip earlier, the burning stretch in his spine as bones realigned with dull creaks, all blending into a haze of humiliated lust that made his nipples tighten against his shirt.

Derek leaned in closer, breath hot on Mark's neck as he fondled lower, rolling Mark's heavy balls in his palm while the tail—now a foot long and furred—whipped against his wrist. "Look how wet you are for this," Derek taunted, gathering the steady drip of pre-cum to slick the entire length, his fist twisting on the upstroke to wring a full-body shudder from Mark. The transformation's ache radiated outward, shoulders hunching as fur threatened beneath the skin, but the pleasure centered on his groin kept him anchored, cock jerking in Derek's grip with every explicit squeeze and pull. Mark's mind spun with the fantasy made flesh, dread and desire twisting tighter as the tail base throbbed like a second cock under Derek's exploring fingers.

"God, it's growing so fast inside me, changing everything—my cock feels so hard I can't stop it!" Mark moaned another victim line, body arching as Derek's thumb pressed into the slit, spreading the fluids in messy circles that made the shaft twitch and leak more. The hand on his tail slid along its length now, tugging gently to send sparks of raw sensation shooting up his reformed spine and straight into his balls, which drew up tight against the base of his throbbing erection. Every detail burned: the velvet drag of skin on skin, the rhythmic squelch of lubrication, the way Mark's pointed ears burned with blood flow, heightening every sound and touch into something unbearably intimate and filthy. Derek's presence loomed, controlling the pace with deliberate slowness, building the pressure without release as the transformation continued its relentless crawl through Mark's trembling frame.

Derek released his grip on the throbbing shaft with a deliberate slowness that left Mark's cock jerking in empty air, the swollen head glistening with a fresh bead of pre-cum that trailed down the underside in a sticky thread. The sudden absence of that firm, twisting pressure made Mark's hips buck forward involuntarily, his balls drawn up tight and aching for more friction even as the tail—now a full eighteen inches of furred length—curled and twitched against Derek's wrist. "Not yet," Derek murmured, his voice low and commanding, wiping his slick fingers on Mark's shirt before gripping his shoulders. "Stand up. Try to act normal, like nothing's happening. I want to see how much of you this takes before you can't pretend anymore."

Mark's knees trembled as he pushed himself upright, the rough carpet biting into his palms one last time before he forced his weight onto unsteady legs. The motion sent fresh waves of grinding pressure through his spine and pelvis, his emerging tail forcing the waistband of his jeans lower until it hung half-off his hips, the base thick and sensitive where it joined his lower back. Every inch of the movement stretched his reforming bones with wet, internal pops, shoulders hunching forward as the cartilage in his ears flicked and burned hotter, the pointed tips now brushing the sides of his face. His cock remained rigidly exposed, bobbing heavily with each step as he tried to straighten, the shaft flushed dark and veined, a constant drip of arousal leaking from the slit to spatter against the floor. The musky scent of his own leaking need filled the air thicker now, mingling with the sweat already soaking his shirt, while the pointed tips of his ears caught every ragged breath and the low creak of joints realigning.

"Like this?" Mark gasped out, voice cracking on the rehearsed line as he stood there swaying, hands hovering uselessly at his sides instead of covering himself. "I... I can't let anyone see me like this, it's too wrong, too humiliating." His thighs quivered from the effort of staying upright, the fur along his lengthening tail prickling with every small shift in balance, the appendage itself heavy and alive, brushing the backs of his calves in involuntary swipes that sent sparks racing up his spine straight into his untouched balls. The ache in his gut coiled tighter, a shameful heat that made his nipples harden visibly against the fabric of his shirt, while his cock throbbed untouched, the head glistening under the lamp's dim glow. Derek circled him slowly, boots thudding, eyes fixed on the way Mark's back arched involuntarily to accommodate the tail's growth, now curling upward with another inch of sensitive flesh pushing free.

Derek's hand returned not to the cock but to the base of the tail, fingers digging in with possessive pressure that made Mark's knees nearly buckle again. "Walk a few steps," he ordered, the command laced with that same hot edge. "Keep your voice steady if you can. Show me how normal you can act while your body betrays you." The squeeze on the tail base sent a jolt of raw, electric sensation through Mark's pelvis, forcing another bead of pre-cum to well up and slide down his length in a slow, torturous trail that he felt every inch of. Mark tried to obey, taking a shaky step forward, then another, his gait awkward as the tail's weight threw off his center and the grinding in his spine forced his posture lower. The denim of his jeans rasped against his thighs with each movement, the open fly letting cool air tease his exposed balls and shaft, heightening the throbbing need that Derek refused to satisfy. Sweat trickled down the cleft of his ass, following the line of his changing spine where faint ridges of fur were beginning to push through the skin in itchy, prickling waves.

The room felt smaller with every step, the air thicker with the scent of arousal and the faint metallic tang of Mark's bitten lip. "Please, don't make me walk like this," he moaned another line, hips jerking as Derek's fingers stroked along the tail's length again, tugging just enough to make the new nerves sing. His cock bounced with the motion, heavy and demanding, the foreskin pulled back fully now so the sensitive head caught every shift in temperature and every subtle draft. The transformation's heat radiated outward from his core, making his skin flush and his breath come in short pants, while the pointed ears flicked at the sound of Derek's low chuckle behind him. Mark's hands clenched into fists at his sides, refusing to reach down and stroke the aching length even though the urge burned through him, the roleplay keeping him teetering on that edge of desperate, humiliated need.

Derek stepped closer again, breath warm against the back of Mark's neck as one hand slid under the shirt to trace the emerging fur along his spine, the other returning to cup and roll his balls with slow, deliberate squeezes that avoided the shaft entirely. "Feel that?" Derek whispered, voice rough. "Your body's not done with you yet. Keep standing. Keep trying." The dual sensations—the firm fondling below and the stroking along his tail—sent fresh tremors through Mark's frame, his cock pulsing visibly with each heartbeat, pre-cum now coating the head in a shiny layer that caught the light. The pressure at his tailbone built again, another wet pop as the appendage lengthened further, fur thickening along its curve while Mark fought to stay upright, every muscle taut with the strain of pretending normalcy amid the relentless, intimate invasion of the change.

The pressure at his tailbone built again, another wet pop as the appendage lengthened further, fur thickening along its curve while Mark fought to stay upright, every muscle taut with the strain of pretending normalcy amid the relentless, intimate invasion of the change. His hands, still hovering uselessly at his sides, began to burn with fresh heat, the palms flattening and stretching outward in slow increments that made his fingers twitch and curl involuntarily. Derek's grip on the tail tightened possessively as he noticed the shift, his free hand sliding down to capture one of Mark's wrists and lift it for inspection. "Look at that," he murmured, voice thick with dark amusement, thumb pressing into the elongating palm where the skin pulled taut and the bones ground with wet, muffled cracks. "Your hands are next—palms getting longer, fingers pulling back like they're trying to hide. Just like in American Werewolf in London, isn't it? That poor bastard screaming while his hands turned into paws, claws ripping out. Bet you jerked off to that scene more times than you can count."

Mark's breath shuddered out in a broken moan, his cock jerking untouched as the fingers shortened fraction by fraction, the joints compressing with sharp little pops that sent jolts of mingled pain and arousal straight up his arms. The thumb on his right hand began to twist inward, the nail thickening and curving as it reshaped into a stubby dewclaw, the skin around it reddening and itching with the first prickle of fur pushing through in fine, dark tufts. He flexed the changing digits helplessly, feeling the reduced reach, the way his grip would never close the same again, while Derek's fingers traced the lengthening palm with deliberate slowness. "Fuck, it's exactly like that movie," Derek taunted, his breath hot against Mark's ear as he squeezed the sensitive new length of palm, forcing a gasp from Mark's throat. "You're turning into the beast right in front of me, and your cock's still leaking like a faucet—look at it, drooling all over the floor while your hands betray you."

The transformation in his palms accelerated under the attention, the fingers now noticeably stubbier, the tips blunting as the nails darkened and pushed outward into blunt points that scraped against Derek's skin. Mark's exposed shaft throbbed harder at the humiliation, a thick bead of pre-cum welling up from the slit and sliding down the veined underside in a slow, glistening trail that Derek's other hand caught and smeared in lazy circles around the heavy balls, avoiding the shaft itself to keep the torment building. Sweat poured down Mark's chest beneath his shirt, the fabric clinging to his hardening nipples as his shoulders hunched further, the tail lashing against Derek's thigh with each fresh wave of grinding pressure in his spine. The scent of his own musk thickened in the air, mixing with the faint copper from his bitten lip and the musky warmth rising from his changing body, every breath dragging the odors deeper into his lungs until his head spun with it.

"Please, not my hands too—it's too much like the film, I can't watch it happen," Mark choked out the rehearsed line, voice cracking as his left palm stretched another fraction longer, the shortened fingers curling inward toward the emerging dewclaw in a parody of a paw. The sensation was intimate and filthy, the nerves in the reshaping flesh hypersensitive under Derek's exploring touch, each press and squeeze sending sparks racing down to his groin where his untouched cock bounced and leaked in rhythmic pulses. Derek chuckled darkly, releasing the wrist only to grip the base of Mark's shaft at last, giving it one firm, twisting stroke from root to the slick head that made Mark's knees buckle. "Keep walking," he ordered, voice husky. "Try to act normal while your fingers turn into nothing. Feel how wet you are for this horror show."

Mark stumbled forward another step, his gait even more unsteady now with the altered hands dangling at his sides, the shortened fingers unable to clench properly as the palms continued their slow elongation. The tail swayed heavily behind him, brushing his calves with every motion and sending fresh jolts through his pelvis, while Derek's hand worked his cock in deliberate, unhurried pumps that matched the pace of the transformation—each tug on the shaft coinciding with another wet pop in his palms or a twitch from the lengthening fingers. The room's dim light caught the sheen of fluids on his glans, the foreskin stretched tight and glistening, every nerve alight with the dual assault of change and stimulation. Mark's pointed ears flicked at the wet sounds of the handjob filling the air, his body arching as the dewclaws fully formed, the thumbs now useless stubs pressing against his palms in a way that made every attempted grip feel alien and wrong.

Derek's fingers tightened around the shaft, thumb smearing pre-cum over the crown in slow circles while his other hand returned to the tail, tugging the furred length in counterpoint to each stroke. "That's it, just like the movie—hands first, then the rest of you," he whispered, his voice laced with that same heated contempt and desire. Mark's cock pulsed in the firm grip, balls drawing tighter as the transformation's heat spread from his reforming hands up his arms, the skin flushing and itching with the promise of more fur to come. He swayed on his feet, every muscle locked in the effort to remain upright, the explicit wet drag of skin on skin blending with the internal creaks of bone and the ragged edge of his own moans until the line between agony and ecstasy blurred into pure, humiliated need.

He swayed on his feet, every muscle locked in the effort to remain upright, the explicit wet drag of skin on skin blending with the internal creaks of bone and the ragged edge of his own moans until the line between agony and ecstasy blurred into pure, humiliated need. Derek's fist pumped steadily along the throbbing shaft, twisting on each upstroke to smear fresh pre-cum across the swollen head while his other hand tugged the furred tail in a matching rhythm, sending jolts of raw sensation through Mark's pelvis that made his exposed balls draw even tighter. A sudden, grinding pressure bloomed in Mark's feet, the soles flattening and stretching inside his shoes with wet, muffled pops as the toes began to shorten and thicken, bones realigning into a digitigrade structure that forced his heels upward in an involuntary arch. The leather strained and split with a sharp crack, the fabric tearing open as clawed digits pushed free, nails darkening and curving into blunt points that scraped against the carpet, the skin itching furiously as dark fur sprouted in coarse patches along the arches and up toward his ankles.

Mark gasped sharply, his cock jerking in Derek's grip as the change raced through his feet, the arches lengthening and the pads forming thick and leathery against the floor with each stumbling step forward. His rib cage followed immediately, the bones expanding outward in a slow, barreling swell that pressed against his shirt and forced the fabric to ride up over his heaving stomach, each breath coming shorter and more labored as the new depth altered his posture and sent a fresh wave of heat flooding through his core. Derek released the shaft just long enough to shove Mark's jeans down further, exposing the full length of the changing body, then resumed stroking with firmer pressure, thumb circling the leaking slit while murmuring low taunts about how the beast was claiming him inch by inch. The tail lashed wildly now, its sensitive base throbbing under Derek's squeezing fingers as the hips began to shift, the pelvis tilting forward in a way that made standing impossible, the bones grinding with dull internal pops that dragged a broken whimper from Mark's throat.

His shoulders hunched lower under the same relentless pressure, the joints popping as they broadened and reshaped for a quadrupedal stance, forcing his weight forward until his altered hands hit the carpet with a slap, palms elongated and claws scraping as his body betrayed him completely. Derek followed the motion, kneeling behind him to keep one hand wrapped around the heavy cock while the other slid beneath to cup and roll the tightening balls, the position trapping Mark on all fours with his tail raised and twitching, the furred length curling over Derek's wrist. The rib cage continued its outward push, stretching the shirt until seams popped and cool air hit the sweat-slicked skin, nipples hard and aching as the transformation's heat pooled deeper in his gut, making his cock throb visibly with each heartbeat and leak a steady stream that Derek caught and used to slick the entire length in long, deliberate strokes. Mark's feet flexed involuntarily, the new paws spreading for balance, claws digging into the carpet as his hips rocked back against the invading touch, the sensation of his changing spine and barreling chest blending with the filthy wet sounds of the handjob until every nerve screamed with humiliated arousal.

Derek leaned over his back, breath hot against the pointed ears as he pumped faster now, fist twisting and squeezing the shaft from root to crown while his free hand traced the expanding ribs, feeling the bones shift beneath the skin. Mark's moans grew louder, voice cracking on another rehearsed plea about not wanting this, even as his body pushed back into the stimulation, tail whipping side to side and cock pulsing hard enough to spatter pre-cum across the floor in rhythmic droplets. The quadrupedal shift locked him down fully, shoulders and hips settling into the new alignment with one final series of wet cracks that left him unable to rise, every muscle quivering as Derek's fingers explored the sensitive new paw pads on his feet, pressing and stroking them until Mark shuddered from the overload. Sweat poured down his flanks, the musky scent of his leaking cock filling the air thicker, mixing with the faint metallic bite of his bitten lip and the warm, animal musk rising from the emerging fur along his spine and limbs.

The pressure built relentlessly in his groin as Derek's strokes slowed again, denying release while the transformation continued its crawl through his trapped form, rib cage fully barreling now and forcing a deeper, panting breath that made his whole body rock on all fours. His cock hung heavy and flushed beneath him, veins standing out along the length as the hand worked it in torturous, measured pulls, each one timed to the next internal pop in his feet or the twitch of his reforming hips. Derek's other hand returned to the tail base, squeezing hard enough to make Mark's balls draw up visibly, the dual sensations pushing him to the edge without tipping over, every detail of the wet friction, the grinding bones, and the humiliating exposure burning into his mind with raw, desperate intensity. The room's dim light caught the sheen of fluids coating his shaft and the dark fur sprouting along his paws, while Mark's pointed ears flicked at every sound, his body locked in that perfect, aching balance of dread and craving as the change held him captive on the floor.

The pressure at his tailbone built again, another wet pop as the appendage lengthened further, fur thickening along its curve while Mark fought to stay upright, every muscle taut with the strain of pretending normalcy amid the relentless, intimate invasion of the change. His hands, still hovering uselessly at his sides, began to burn with fresh heat, the palms flattening and stretching outward in slow increments that made his fingers twitch and curl involuntarily. Derek's grip on the tail tightened possessively as he noticed the shift, his free hand sliding down to capture one of Mark's wrists and lift it for inspection. "Look at that," he murmured, voice thick with dark amusement, thumb pressing into the elongating palm where the skin pulled taut and the bones ground with wet, muffled cracks. "Your hands are next—palms getting longer, fingers pulling back like they're trying to hide. Just like in American Werewolf in London, isn't it? That poor bastard screaming while his hands turned into paws, claws ripping out. Bet you jerked off to that scene more times than you can count."

Mark's breath shuddered out in a broken moan, his cock jerking untouched as the fingers shortened fraction by fraction, the joints compressing with sharp little pops that sent jolts of mingled pain and arousal straight up his arms. The thumb on his right hand began to twist inward, the nail thickening and curving as it reshaped into a stubby dewclaw, the skin around it reddening and itching with the first prickle of fur pushing through in fine, dark tufts. He flexed the changing digits helplessly, feeling the reduced reach, the way his grip would never close the same again, while Derek's fingers traced the lengthening palm with deliberate slowness. "Fuck, it's exactly like that movie," Derek taunted, his breath hot against Mark's ear as he squeezed the sensitive new length of palm, forcing a gasp from Mark's throat. "You're turning into the beast right in front of me, and your cock's still leaking like a faucet—look at it, drooling all over the floor while your hands betray you."

The transformation in his palms accelerated under the attention, the fingers now noticeably stubbier, the tips blunting as the nails darkened and pushed outward into blunt points that scraped against Derek's skin. Mark's exposed shaft throbbed harder at the humiliation, a thick bead of pre-cum welling up from the slit and sliding down the veined underside in a slow, glistening trail that Derek's other hand caught and smeared in lazy circles around the heavy balls, avoiding the shaft itself to keep the torment building. Sweat poured down Mark's chest beneath his shirt, the fabric clinging to his hardening nipples as his shoulders hunched further, the tail lashing against Derek's thigh with each fresh wave of grinding pressure in his spine. The scent of his own musk thickened in the air, mixing with the faint copper from his bitten lip and the musky warmth rising from his changing body, every breath dragging the odors deeper into his lungs until his head spun with it.

"Please, not my hands too—it's too much like the film, I can't watch it happen," Mark choked out the rehearsed line, voice cracking as his left palm stretched another fraction longer, the shortened fingers curling inward toward the emerging dewclaw in a parody of a paw. The sensation was intimate and filthy, the nerves in the reshaping flesh hypersensitive under Derek's exploring touch, each press and squeeze sending sparks racing down to his groin where his untouched cock bounced and leaked in rhythmic pulses. Derek chuckled darkly, releasing the wrist only to grip the base of Mark's shaft at last, giving it one firm, twisting stroke from root to the slick head that made Mark's knees buckle. "Keep walking," he ordered, voice husky. "Try to act normal while your fingers turn into nothing. Feel how wet you are for this horror show."

Mark stumbled forward another step, his gait even more unsteady now with the altered hands dangling at his sides, the shortened fingers unable to clench properly as the palms continued their slow elongation. The tail swayed heavily behind him, brushing his calves with every motion and sending fresh jolts through his pelvis, while Derek's hand worked his cock in deliberate, unhurried pumps that matched the pace of the transformation—each tug on the shaft coinciding with another wet pop in his palms or a twitch from the lengthening fingers. The room's dim light caught the sheen of fluids on his glans, the foreskin stretched tight and glistening, every nerve alight with the dual assault of change and stimulation. Mark's pointed ears flicked at the wet sounds of the handjob filling the air, his body arching as the dewclaws fully formed, the thumbs now useless stubs pressing against his palms in a way that made every attempted grip feel alien and wrong.

Derek's fingers tightened around the shaft, thumb smearing pre-cum over the crown in slow circles while his other hand returned to the tail, tugging the furred length in counterpoint to each stroke. "That's it, just like the movie—hands first, then the rest of you," he whispered, his voice laced with that same heated contempt and desire. Mark's cock pulsed in the firm grip, balls drawing tighter as the transformation's heat spread from his reforming hands up his arms, the skin flushing and itching with the promise of more fur to come. He swayed on his feet, every muscle locked in the effort to remain upright, the explicit wet drag of skin on skin blending with the internal creaks of bone and the ragged edge of his own moans until the line between agony and ecstasy blurred into pure, humiliated need. A sudden, grinding pressure bloomed in Mark's feet, the soles flattening and stretching inside his shoes with wet, muffled pops as the toes began to shorten and thicken, bones realigning into a digitigrade structure that forced his heels upward in an involuntary arch. The leather strained and split with a sharp crack, the fabric tearing open as clawed digits pushed free, nails darkening and curving into blunt points that scraped against the carpet, the skin itching furiously as dark fur sprouted in coarse patches along the arches and up toward his ankles.

The pressure intensified across Mark's changing feet as the arches fully elongated into digitigrade stance, the new paw pads pressing thick and leathery against the torn remnants of his shoes while coarse fur spread upward in itchy waves over his calves. Derek's fist never slowed on the throbbing cock, twisting firmly around the slick head with each deliberate pump that drew another thick bead of pre-cum from the slit, the wet sound echoing as he smeared it down the veined length to keep the shaft glistening and hypersensitive. Mark's hips rocked back involuntarily, his tail lashing against Derek's arm as fresh jolts raced from the base where Derek's other hand squeezed possessively, the furred appendage now heavy and curling upward with every stroke that matched the grinding internal shifts.

His shoulders began to narrow and raise, the joints popping with wet, muffled cracks as the bones compressed inward and lifted higher to support the inevitable quadrupedal posture, forcing his weight forward onto the elongated palms and shortened fingers that now curled into imperfect paws. The change dragged a broken gasp from Mark's throat, his cock jerking harder in Derek's grip as the shoulders settled into their new alignment, the muscles twitching and bunching under the skin while faint ridges of dark fur prickled through in patches along the blades. Derek leaned closer, breath hot on the pointed ear tip as he murmured taunts about the beast claiming every inch, his thumb circling the leaking crown in slow, torturous spirals that made Mark's balls draw tighter and his untouched nipples ache against the sweat-soaked shirt.

Mark's rib cage continued its barreling expansion with dull internal creaks, the shirt riding higher to expose more flushed skin as his posture locked lower, the raised shoulders locking him into a stance where standing upright would soon become impossible. Every tug on his shaft sent sparks racing through the reforming body, the slick friction of skin on skin blending with the musky scent of arousal and the faint animal musk rising from the sprouting fur along his limbs and spine. His new paw feet flexed against the carpet, claws scraping as the digitigrade shift settled fully, forcing his heels higher and making each subtle movement send fresh waves of sensitivity through the pads while Derek's hand on the tail tugged in counterpoint, rolling the base with enough pressure to make the entire length twitch and throb like an extension of his aching erection.

Sweat streamed down Mark's flanks in rivulets, soaking the shirt that clung to his heaving chest and highlighting the hardened nipples as his breath came in short, panting gasps that matched the rhythm of the handjob. Derek's fingers worked relentlessly, one fist pumping from root to tip with twisting pressure that exposed the glistening head fully on each upstroke, while the other hand explored the sensitive new fur along the tail and the narrowing shoulders, pressing into the changing muscle to draw whimpers and involuntary hip jerks. The transformation's heat pooled deeper in his gut, making his exposed balls tighten visibly and his cock pulse with each heartbeat, pre-cum now dripping in steady strands onto the floor beneath his quadrupedal form as the shoulders finished their raise, locking him lower and more stable on all fours.

Derek shifted his grip to cup Mark's heavy balls with one hand while the other maintained firm strokes along the shaft, the dual attention sending raw sensation flooding through the trapped body as the shoulders' final pops echoed the wet sounds of lubrication and flesh. Mark's pointed ears flicked at every ragged moan escaping his own lips, the humiliation twisting tighter with the knowledge that his body was betraying him exactly as in those films, the raised and narrowed shoulders completing the posture that left him unable to rise, cock hanging heavy and throbbing under the relentless, measured torment that denied release while promising more change to come. The air thickened further with the mingled odors of sweat, pre-cum, and emerging fur, every breath dragging the scents deeper as Derek's low chuckles blended with the creaks of bone and the rhythmic squelch of the hand working Mark's leaking length without mercy.

The air thickened further with the mingled odors of sweat, pre-cum, and emerging fur, every breath dragging the scents deeper as Derek's low chuckles blended with the creaks of bone and the rhythmic squelch of the hand working Mark's leaking length without mercy. Mark's hips bucked forward without warning, a deep grinding pressure blooming through his pelvis as the bones there realigned with a series of wet, internal pops that forced his stance wider and lower. The shift dragged a raw cry from his throat, his voice cracking as he gasped out, "I can't stand up anymore—my hips are changing, locking me down, I can't get back on two legs!" Derek's grip tightened on the heavy balls, rolling them firmly while his other fist pumped the throbbing cock faster, thumb pressing into the slick slit to force another spurt of pre-cum that coated his fingers in sticky warmth.

Mark's thighs trembled violently as the pelvis tilted forward, the new angle making his cock hang even heavier beneath him, the veined shaft pulsing visibly with each heartbeat while Derek's strokes lengthened to match the deeper arch of his back. The fur along his spine thickened in dark patches, prickling against Derek's palm as the other hand slid up to grip the base of the tail again, tugging it upward to expose the sensitive skin where it joined his changing body. Every tug sent electric jolts racing through Mark's groin, his balls drawing tighter in their sack as the hips settled into their quadrupedal support, the muscles bunching and twitching under the skin while faint ridges of thicker fur sprouted along the inner thighs. The wet drag of Derek's fist around his cock grew slicker, the foreskin sliding back fully with each twist that exposed the glistening head to the cool air, sending shudders through Mark's entire frame.

Derek leaned in closer, his breath hot against the base of Mark's neck as he murmured, "That's it, feel those hips betray you just like you always wanted," his voice thick with shared heat rather than pure mockery now. Mark's pointed ears flicked at the words, catching every detail of the handjob—the rhythmic squelch of pre-cum being worked along the length, the way Derek's thumb circled the crown to spread the fluids in lazy spirals that made his shaft jerk and leak more. His new paw feet scraped at the carpet, claws digging in for balance as the hips completed their shift, locking him fully on all fours with his tail raised high and twitching against Derek's wrist. Sweat trickled down the cleft of his ass, following the line of his spine where the fur grew denser, the musky scent of his arousal mixing with the animal warmth rising from his transforming form.

The pressure built hotter in Mark's gut as Derek's strokes slowed deliberately, denying release while one hand cupped and squeezed his balls with possessive pressure, the dual sensation making his cock throb harder against the empty air. Mark moaned another line from the fantasies that had shaped this night, voice hoarse as he cried, "It's too much, my body won't let me stand—I'm stuck like this, changing while you touch me," even as his hips rocked back into the touch, craving the friction that kept the edge sharp and unbearable. Derek's fingers traced the new curve of his spine, pressing into the barreling ribs that heaved with each panting breath, while the hand on his cock resumed its firm pumps, twisting on every upstroke to wring fresh beads of fluid from the slit that trailed down in glistening strings.

Mark's nipples ached against the sweat-soaked shirt as his chest expanded further, the fabric riding higher to expose flushed skin where dark fur began to push through in fine tufts along his belly. The transformation's heat pooled deeper, making his exposed balls tighten visibly under Derek's rolling grip while the tail curled and lashed with every stroke that matched the internal creaks still echoing through his hips and shoulders. Derek's chuckle vibrated against Mark's ear as he leaned over the arched back, his fist working the length in measured, torturous pulls that kept Mark teetering on the brink, the wet friction blending with the scent of leaking need and emerging fur until the room felt heavy with it.

Every nerve in Mark's changing body sang with the overload, the hypersensitive pads of his new paws flexing against the carpet as Derek's free hand returned to stroke along the tail's furred length, tugging just enough to send sparks shooting straight into his groin. The cock in Derek's grip pulsed hot and heavy, veins standing out along its length as pre-cum coated everything in a shiny layer that caught the dim lamp glow, the shaft jerking with each deliberate squeeze that built the pressure without tipping over. Mark's breath came in ragged pants, his pointed ears burning with blood flow as he surrendered deeper into the role, hips locked in their four-legged stance while the relentless stimulation and the slow crawl of the change held him captive in that perfect, aching haze of humiliated desire.

The air thickened further with the mingled odors of sweat, pre-cum, and emerging fur, every breath dragging the scents deeper as Derek's low chuckles blended with the creaks of bone and the rhythmic squelch of the hand working Mark's leaking length without mercy. Derek's fingers slid back from the tail base, tracing lower between the cheeks of Mark's ass until one blunt fingertip pressed against the tight pucker there, circling the sensitive rim with deliberate pressure that made Mark's entire frame jolt forward on his altered paws. "Fuck, look at this hole clenching for me already," Derek murmured, voice rough with heat as he teased the entrance without pushing in, the pad of his finger rubbing slow, wet circles that drew a fresh bead of pre-cum from Mark's cock and sent his balls drawing up even tighter. "How much more does this body have left to twist before it's fully the beast? The ears, the tail, those paws—your ribs are still pushing out, but what about that muzzle? That fur spreading thicker across your back? I wonder how long until your face cracks and lengthens, until you're drooling and howling instead of begging."

Mark's breath came in ragged pants, his cock throbbing visibly in Derek's fist as the teasing touch at his hole made his hips rock back instinctively, desperate for more contact, for anything that might push him over the edge he'd been denied for so long. "Derek, please—touch it, finger me, I need something inside," he gasped out, voice cracking on the raw plea even as he tried to hold the rehearsed lines, his desperation bleeding through the script into genuine, aching need. The digit pressed firmer against the hole but still refused entry, just circling and tapping the rim until Mark's tail lashed wildly and his cock jerked hard enough to spatter another strand of fluid onto the carpet. Derek kept the strokes on the shaft slow and measured, twisting just enough on the upstroke to keep the pleasure simmering without cresting, his free hand now cupping and rolling Mark's balls with firm squeezes that avoided the base of the shaft entirely.

Sweat dripped from Mark's chin onto the floor as he fought to stay steady on all fours, the new paw pads flexing and scraping while another wave of pressure rippled through his narrowing shoulders and barreling chest, the shirt tearing further at the seams with wet pops of thread. Derek's fingertip finally breached the ring of muscle with a slow, slick push, sliding just to the first knuckle and crooking to rub inside while his thumb continued circling the crown of Mark's cock, smearing pre-cum in lazy spirals that made the shaft pulse and leak steadily. "Not yet," Derek said, the words low and firm as he worked the finger deeper in shallow thrusts, stretching the hole around the intrusion without speeding up the handjob. "You're dripping for this, hole fluttering around my finger like it wants more, but you don't get to cum until every inch of you has changed. Feel that? The way your ass is clenching, begging for release while your body keeps breaking open?"

Mark moaned louder, the sound raw and unfiltered as the single finger pumped in and out with torturous slowness, each press against his inner walls sending sparks straight to his neglected prostate and making his untouched nipples ache under the clinging shirt. His desperation mounted with every denied stroke, hips bucking back to chase the finger while his cock throbbed in empty, aching pulses, the head glistening and swollen as Derek's fist maintained that perfect, frustrating rhythm—just enough friction to keep him hard and leaking, never enough to tip over. "God, Derek, I can't take it—finger me harder, let me cum, please, I'm so close it hurts," Mark begged, voice hoarse with the need that twisted through him, the transformation's heat only amplifying the arousal until every nerve felt exposed and raw.

Derek added a second finger without warning, scissoring them inside the tight heat of Mark's hole to stretch him wider while the hand on his cock slowed even further, thumb pressing firmly against the frenulum to hold back the building orgasm. "Still so much left," Derek wondered aloud, breath hot against the furred nape of Mark's neck as he curled both fingers against that sensitive spot inside, milking more pre-cum from the shaft without granting relief. "Your jaw's starting to ache, isn't it? That snout pushing forward next, teeth sharpening while your hole takes my fingers? You'll be on the edge the whole time, desperate and dripping, until the last bone cracks and you finally get to spill." Mark's body shook with the effort of holding back, his paws digging into the carpet as the dual sensations—fingers thrusting deep into his ass, the slow torment on his cock—pushed him to the brink again and again, each denial leaving him more frantic, more hungry for Derek's touch and the release that stayed just out of reach.

Mark's body shook with the effort of holding back, his paws digging into the carpet as the dual sensations—fingers thrusting deep into his ass, the slow torment on his cock—pushed him to the brink again and again, each denial leaving him more frantic, more hungry for Derek's touch and the release that stayed just out of reach. The second finger curled deeper, rubbing insistently against that swollen spot inside while Derek's other hand maintained its agonizingly slow pace, fist gliding from root to crown with just enough pressure to keep the shaft iron-hard and leaking in heavy strands that splattered the carpet below. Mark's hips rocked back greedily, his altered pelvis locked in its wide, quadrupedal tilt, tail curling high to expose everything as the fur along his lower back thickened into a dense, dark pelt that prickled under Derek's exploring palm.

Derek's breath ghosted hotter along the nape of Mark's neck, lips brushing the skin just above where the fur began its upward march. "That's it, clench around my fingers like the needy bitch you're becoming," he rasped, scissoring the digits wider to stretch the fluttering rim, the wet sounds of slick penetration filling the room alongside the rhythmic squelch of pre-cum being worked along Mark's throbbing length. The transformation's heat surged again through Mark's core, his barreling ribs heaving as the shirt finally tore completely open, cool air hitting the sweat-slicked expanse of his chest where nipples stood painfully erect. Fur sprouted in earnest now along the sides of his torso, coarse black hairs pushing through in itchy waves that spread toward his collarbones, the dark pelt creeping higher until it bordered the underside of his jaw in a thick, velvety line without yet touching his face itself.

Mark whimpered, voice cracking as he tried to hold the scripted line but failed, genuine desperation bleeding through. "Derek, please—more fingers, fuck me with them, I need to feel it stretching while everything changes," he begged, paws flexing against the carpet, claws scraping as his digitigrade feet shifted for better balance. His jaw ached faintly with the promise of things to come, but the muzzle remained absent, his human features flushed and sweat-streaked, pointed ears flicking wildly at every wet thrust of fingers and every deliberate twist of the hand around his cock. Derek obliged by sinking the two fingers to the knuckle, crooking them hard against the prostate with each slow pump, while his thumb pressed mercilessly against the frenulum to keep the orgasm locked away, the shaft jerking and pulsing in his grip as fresh pre-cum welled up and spilled over his knuckles in glistening rivulets.

The fur continued its relentless crawl, spreading from the dense patch at Mark's nape in fine, dark tufts that traced along his jawline without crossing onto his cheeks or lips, bordering the face like a living collar of beastly pelt that made every touch from Derek's mouth feel electric. Sweat trickled down Mark's arched spine, soaking into the new fur and releasing a stronger, animal musk that mingled with the salty tang of his leaking cock and the sharp scent of Derek's arousal. Derek's free hand slid up from the tail to cup one of Mark's heavy balls, rolling it firmly while the fingers in his ass began a steady thrusting rhythm, scissoring wider with each withdrawal to prepare him for more. Mark's untouched nipples throbbed against the torn remnants of his shirt, his entire frame quivering on all fours as the pressure in his groin built hotter, denied release leaving him frantic and dripping.

Derek's voice dropped lower, laced with rough affection beneath the taunt. "Look at that fur creeping right up to your pretty face, stopping just short like it knows you're still mine to watch," he murmured, adding a third finger with deliberate slowness, the thick intrusion stretching Mark's hole wider as the hand on his cock resumed its torturous pumps, twisting on every upstroke to smear the slick fluids along the swollen head. Mark's balls drew up tight against the base of his shaft, his hips bucking back to chase the fingers deeper while his tail lashed against Derek's wrist, the sensitive furred length twitching with every internal grind of changing bone. The room's dim light caught the sheen of sweat and pre-cum coating everything, Mark's pointed ears burning as he panted through parted lips, jaw aching but still unchanged, the fur a dark border framing his flushed human features in stark contrast to the beast form claiming the rest of him.

Another wave of grinding pressure rippled through Mark's narrowing shoulders as they settled fully into their raised, quadrupedal alignment, the muscles bunching under the spreading pelt while Derek's fingers thrust deeper, crooking insistently to milk more desperate moans from his throat. The handjob never sped up, each deliberate stroke keeping Mark balanced on that razor edge of humiliated need, pre-cum flowing steadily as his cock jerked and throbbed in the slick grip. Mark's body rocked forward with every push of fingers into his ass, the wet friction and the relentless crawl of transformation blending into one overwhelming sensation, fur thickening along his flanks until it met the border at his jaw, leaving his face the last untouched territory as Derek leaned in to nip lightly at the sensitive skin just below the dark pelt's edge.

Derek's teeth grazed that furred edge with a teasing nip that sent a shiver racing down Mark's spine, but then the other man shifted, pulling his fingers free from Mark's stretched hole with a wet pop that left him clenching around nothing. Derek's hand left the cock entirely too, abandoning the throbbing length to bob and drip as he stood and crossed the room, returning moments later with a full-length mirror he'd dragged from the hallway. He positioned it directly in front of Mark on the floor, angling it so the reflection captured every detail of the kneeling beast-form body—pointed ears, furred tail raised high, paws splayed, and the flushed human face still framed by that dark pelt collar staring back in wide-eyed shock. "Watch yourself," Derek ordered, voice low and commanding as he knelt back behind Mark, one arm reaching around to grip the base of the shaft again while the other slid up Mark's sweat-slicked torso.

The sudden pinch to both nipples came without warning, Derek's fingers twisting the hard, untouched buds sharply between thumb and forefinger, rolling them with deliberate pressure that made Mark's entire body jolt forward. The sensation burned straight down to his neglected cock, which twitched violently in Derek's resuming grip, the shaft pulsing thicker as a new heat bloomed at the base. Mark's eyes locked on the mirror as commanded, watching his reflection's face flush darker while the cock in the glass began to change in earnest—the head flaring wider, the veins along the length bulging and darkening as the shaft itself thickened into something more bestial, the skin pulling taut and the slit weeping heavier strands of pre-cum that splattered audibly onto the carpet. "No, not my cock too—it's getting bigger, reshaping into that beastly thing," Mark blurted out, voice cracking on the line as he stared at the mirror, hips rocking back involuntarily into the fingers that now returned to his hole, thrusting three deep while the other hand kept twisting his nipples mercilessly.

The transformation crawled up the length with agonizing slowness, Mark forced to watch every moment in the reflection as the foreskin thickened and the shaft elongated further, curving slightly with a wet internal shift that made his balls draw up even tighter. Derek's pinch on the nipples intensified, tugging them outward as the cock's change peaked, the head swelling into a blunt, sensitive knot at the base while the entire member hung heavier and more obscene beneath him, leaking in constant pulses that Derek smeared along the new girth. "Look at it," Derek rasped against his ear, breath hot, "that cock's turning feral while you beg like a victim in one of your stories." Mark's pointed ears flicked wildly, his gaze fixed on the mirror's image of his own desperate face, the human features still intact but jaw aching now as the change finally reached upward.

His tongue began to lengthen first, swelling and flattening inside his mouth with a humiliating wet stretch that forced his lips apart in the reflection. "Oh god, my tongue—it's getting longer, thicker, I can't stop it," Mark gasped out the rehearsed plea, the words slurring around the growing muscle as it pushed past his teeth, pink and glistening, curling involuntarily against his lower lip in a way that made drool trickle down his chin. The mirror captured every humiliating detail, his eyes wide with that mix of dread and arousal while Derek's fingers worked his hole and nipples in tandem, the cock now fully bestial and throbbing visibly in the glass. "Please, not my face—my tongue's betraying me, turning me into the monster while you watch," he moaned, the line tumbling out wetly as the tongue continued its obscene elongation, now hanging several inches from his parted mouth, too large and sensitive to contain, flicking against his teeth with every ragged breath.

Derek's grip on the shaft tightened, stroking the changed cock with firm twists that matched the tongue's growth, while the mirror held Mark captive to the sight of his own features beginning to crack and shift around that lewd, dangling tongue. The jaw ached deeper, bones grinding as the muzzle threatened to push forward, but the tongue changed first in full, curling and dripping saliva in long strings that splattered the floor beneath his paws. "It's happening too fast, my body's not mine anymore—my tongue's so big I can't even talk right," Mark choked out another victim line, voice muffled and desperate as he watched himself in the glass, nipples burning from the relentless pinches and his new cock jerking in Derek's fist, the whole scene a perfect, aching tableau of transformation and denied release that left him rocking back harder onto those thrusting fingers.

Mark's body rocked back harder onto those thrusting fingers, the three thick digits pumping steadily into his stretched hole as Derek's other hand maintained its torturous grip on the newly bestial cock, stroking the thickened shaft with slow, deliberate twists that kept the swollen head leaking in constant, heavy strands. Derek's voice rumbled low and commanding against Mark's pointed ear, narrating each shift with explicit relish. "Watch that tongue hang out of your mouth like the animal you're becoming, drooling all over the floor while your cock pulses in my fist—it's not done yet, that muzzle is pushing forward now, bones cracking as your jaw lengthens and your teeth sharpen into fangs. Feel it? Your human face cracking open, turning you into the beast while your hole clenches around my fingers like it needs to be fucked through every inch of the change."

The jaw ground outward with wet, internal pops, the reflection showing the muzzle elongating slowly, stretching Mark's skin taut as the nose darkened and flattened into a wet snout, nostrils flaring with each panting breath that carried the musky scent of his own arousal. Derek pinched the nipples harder, tugging them outward as the tongue lolled thicker and longer, saliva dripping in long strings onto the carpet while Mark's eyes stayed locked on the mirror. "That's it, beg for me while your snout forms—your voice is still human, still yours, so cry out how much it hurts, how your cock feels too big and feral as it throbs for release. Your mind's starting to fray, isn't it? The beast thoughts creeping in, making you want to rut and howl, but you won't cum until that last scrap of humanity is gone."

Mark whimpered through the lengthening muzzle, the words slurring around the massive tongue as fresh fur crept up his neck to meet the dark collar already framing his jaw. "Derek, please—it burns, my face is stretching, turning me into that monster from the movies, my cock's knot swelling bigger while you finger me open. I can't think straight, the need is eating my mind, I need to cum but don't let me yet, make me beg more." Derek's narration continued without pause, his fingers scissoring deeper inside the clenching hole, crooking against the prostate with each thrust as the hand on the shaft slowed to a maddening glide. "Look at those eyes glazing over, the humanity slipping away as your brow ridges thicken and your ears twitch higher—your voice is holding out, just like I wanted, so keep crying while the last bones shift. Your balls are drawing tighter, ready to empty every last human thought into the carpet when I finally let you."

The muzzle completed its push with a final series of cracks, the snout fully formed and wet, whiskers sprouting as the reflection showed the beast's face fully overtaking the human one except for the desperate, still-human voice pleading through it. Derek released one nipple to grip the base of the bestial cock firmly, thumb pressing just below the new knot as he added pressure to the fingers in Mark's ass, stretching the rim wider. "Now the mind's going, the beast taking over completely—your thoughts turning to nothing but rutting and pack and heat, but your voice stays human for this last part so you can sob and beg like the victim in your fantasies. Feel that orgasm building? It's coming with the final change, your voice cracking into growls as you cum your humanity out all over the floor."

Mark's hips jerked wildly, the transformed cock swelling impossibly harder in Derek's fist as the pressure peaked, his paws scraping the carpet and tail lashing as he cried out in that last human voice, raw and breaking. "No, Derek, don't make me—it's too much, my mind's fading, I'm nothing but need, please let me cum while I still sound like me!" Derek's narration turned urgent and filthy, pumping the shaft faster now, fingers thrusting deep and curling hard against the prostate. "That's the voice I wanted—beg and cry as it happens, feel your balls unload every scrap of who you were while the beast claims the sound too. Cum for me, Mark, cum your humanity out now."

The orgasm crashed through him in violent pulses, thick ropes of cum erupting from the bestial cock to splatter the mirror and carpet as Mark's voice fractured mid-sob, the final human words twisting into a deep, guttural howl that marked the last change, his mind dissolving into primal haze while Derek held him through every shuddering spurt.

The orgasm crashed through him in violent pulses, thick ropes of cum erupting from the bestial cock to splatter the mirror and carpet as Mark's voice fractured mid-sob, the final human words twisting into a deep, guttural howl that marked the last change, his mind dissolving into primal haze while Derek held him through every shuddering spurt. The beast's knot swelled fat at the base, locking Derek's fist in place as the final spurts tapered into a steady ooze, Mark's barrel chest heaving with ragged pants that fogged the mirror's reflection. His new snout twitched, nostrils flaring wide to drink in the thick musk of spent seed and Derek's own rising arousal, the scent igniting something feral and unstoppable deep in his transformed gut. The voice that had begged in human tones was gone, replaced by a low, rumbling growl that vibrated through his furred frame, but the urge surging through his quadrupedal body was crystal clear: mount, claim, transform.

Mark's powerful haunches bunched beneath him, the digitigrade paws scraping the carpet as he twisted with sudden, fluid strength, his elongated muzzle swinging around to catch Derek's wrist in a gentle but unyielding bite that dragged the man forward. Derek's eyes widened, a flush creeping up his neck even as a smirk tugged at his lips—he knew this part of the game, had scripted it in whispers during their planning, but the reality hit with raw heat as the beast shoved him onto his back amid the scattered cum. Mark's heavy, still-dripping cock dragged across Derek's thigh, smearing the thick fluid into the denim before the beast's clawed forepaws pinned the man's shoulders, furred chest pressing down with crushing weight that forced Derek's breath out in a sharp gasp. The knot at the base of that bestial shaft throbbed hot and insistent against Derek's hip, pre-cum welling fresh from the flared head to soak through fabric, the scent of it mixing with sweat and the animal musk pouring off Mark's pelt in waves that made Derek's own cock twitch visibly in his pants.

With a low, possessive snarl, Mark's muzzle dipped to Derek's throat, blunt teeth grazing the pulse point while his hind legs shifted, the powerful haunches straddling Derek's hips to grind that monstrous length along the man's trapped erection. The transformation's heat still lingered in Mark's veins, fueling the feral need to spread it, to make Derek feel every humiliating pop and stretch of bone and fur. Derek's hands came up to fist in the thick ruff along Mark's neck, not pushing away but pulling closer, his voice cracking with genuine thrill as he muttered, "Fuck, yes—do it, make me feel it." The beast's claws shredded the shirt in one swift rip, exposing Derek's chest where nipples pebbled under the sudden cool air, and Mark's rough tongue—still thick and dripping—lapped over one, dragging wet and insistent while his hips rocked forward to press the knot against Derek's zipper with deliberate pressure that made the man's cock jerk and leak inside the confines.

Derek's jeans yielded under the beast's insistent grinding, the fabric tearing with a sharp rasp as the bestial cock shoved free, hot and veined and already starting to leak fresh pre-cum that pooled against the man's exposed skin. Mark's forepaws pinned Derek's wrists above his head now, the weight of the transformed body forcing the man flat, thighs spread wide as the beast's hindquarters adjusted for the mounting. The first press of that flared head against Derek's entrance was slick with cum and spit, stretching the tight ring with slow, relentless force that drew a broken moan from Derek's throat, his body arching despite the roleplay's script. "God, it's too big—it's changing me already, I can feel it burning in," Derek gasped out his own rehearsed line, voice thick with the mix of humiliation and raw lust as the knot nudged insistently, popping past the rim with a wet stretch that made his hole clench and flutter around the invading girth. Mark's tail lashed once, then curled possessively over Derek's leg as the beast thrust deeper, the shaft pulsing hot inside as the first internal shifts began to ripple through Derek's pelvis—bones grinding with faint pops that sent sparks of mingled pain and pleasure racing up his spine.

The change took Derek slower at first, the heat blooming from the point of penetration outward in waves that made his balls draw tight and his cock throb untouched against his belly, pre-cum beading at the slit. Mark's muzzle lowered to lap at the man's chest again, tongue curling around one nipple while the beast's hips rolled in shallow thrusts that dragged the knot against Derek's prostate with every push, forcing thick strands of fluid from the human cock to splatter upward. Derek's breath hitched sharper as his ears began to burn, cartilage stretching with wet pops that matched the rhythm of the mounting, pointed tips brushing his hair just as Mark's had. "No, not my ears—it's happening, I can't stop it," he moaned, hips bucking up to meet the thrusts even as the humiliation of the roleplay twisted deeper, his body betraying him with the same unwanted heat that had gripped Mark. The beast growled approval, thrusting harder now, the knot swelling further inside to lock them together while fur began to prickle along Derek's spine, the first dark patches pushing through sweat-slicked skin in itchy, sensitive waves that made every drag of Mark's pelt against his back an electric torment.

Derek's hands clawed at the carpet as the transformation crawled higher, shoulders hunching forward involuntarily while his rib cage started to barrel outward with dull creaks, the pressure forcing his shirt remnants aside to expose more skin flushing dark with arousal. Mark's bestial cock throbbed steadily inside him, each pulse feeding the change as the knot ground deep, sending jolts of raw sensation through Derek's reforming pelvis that made his thighs quiver and his untouched shaft jerk harder, leaking steadily onto his own stomach. The air grew thicker with the mingled scents of their combined musk, pre-cum, and the emerging animal fur, every breath dragging it deeper into Derek's lungs until his head spun with the same humiliated lust that had consumed Mark. His cock, still human but achingly hard, bounced with each thrust, the head glistening as the beast's pace built toward another shared edge, the feral urge to claim fully overriding everything else in a haze of grinding hips, wet sounds of penetration, and the slow, relentless crawl of bone and fur claiming Derek inch by inch.

A Transformative Experience