Cover of The Experimental Endeavor (F)

The Experimental Endeavor (F)

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A woman and her girlfriend have a stale sex life and the girlfriend clearly isn't satisfied with toys for penetration; the woman decides to get a new experimental injection to grow a penis. Not only does it work, it also has other unintended side effects like breast growth. The girlfriend loves it, but wants even more.

Chapter 19: Inexplicable

A low groan scraped its way from Evie’s throat before she was even fully conscious. It was a sound of deep, visceral discomfort. Her whole body felt heavy, thrumming with a strange internal pressure. The dull ache in her lower back was a familiar companion now, a phantom echo of the weight settled between her legs. But this morning, it was sharper, more insistent.

She opened her eyes to the grayish predawn light filtering through the blinds. Clare was a warm line against her side, breathing softly.

And Evie was painfully, obtrusively hard.

It wasn't just an erection. It was an imposition. Her cock lay hot and rigid against her own stomach, a substantial, veined weight that felt denser, more substantial than it had even the night before. It strained upward, the skin taut and sensitive. A dull, demanding throb pulsed in time with her heartbeat.

She shifted, trying to find a position that didn’t amplify the ache. The movement jostled Clare, who murmured something unintelligible before her breathing hitched. Evie felt Clare’s hand, warm and sleep-soft, slide across her abdomen. It drifted lower, sleepily seeking familiar territory.The fingers stopped. Clenched. Clare’s body went still.

Then she was awake. Evie felt the sharp intake of breath.

“Jesus Christ,” Clare whispered, her voice raspy with sleep.

Her hand wasn’t exploring anymore. It was measuring. Her fingers wrapped around the base, and Evie saw her wrist bend at an unnatural angle to accommodate the girth. Clare pushed herself up on one elbow, her blonde hair a tangled curtain. Her blue eyes were wide, all sleepiness burned away by a stunned, hungry focus. The amber lamplight from the night before was off, but in the gray light, her expression was stark.

“Evie.” Her name was a statement, not a question.

“I know,” Evie muttered, her own voice thick. “It aches.”

“It’s… bigger.” Clare’s other hand came up, her thumb brushing over the swollen head, tracing the prominent ridge of the corona. A bead of clear fluid seeped from the slit. Clare smeared it with her thumb, her touch clinical and fascinated. “Substantially bigger. It was… what, like my wrist last night? This is…” She moved her own forearm, lining it up beside Evie’s shaft. In the murky light, the comparison was undeniable. The thick column of flesh was nearly as wide as the lean muscle of Evie’s forearm, only shorter. A monstrous, shocking proportion.

Clare’s gaze swept upward, over Evie’s torso. She pushed the tangled sheet down. Her eyes narrowed. “Your tits.”

“What?”

“They’re bigger, too. Fuller.” Clare’s hand left Evie’s cock, a loss of contact that made Evie gasp. She cupped Evie’s breast, her thumb skating over a nipple that was more pronounced, darker. The soft mound did feel heavier in her palm, spilling more generously over the sides of her hand.“The serum. It’s not stopping. It’s still… redistributing you.”

A cold knot of fear tightened in Evie’s gut. It was one thing to accept a change. It was another to be an ongoing experiment, a canvas still being violently painted. But the fear was instantly, brutally, undercut by the raw, approving heat in Clare’s eyes. That look chased the chill away, replacing it with a different kind of tension.

“God, look at you,” Clare breathed, her voice dropping to a husky register. She leaned down, her mouth hovering over Evie’s nipple. Her tongue darted out, a quick, hot lick. Evie arched off the bed with a sharp cry, sensation arcing directly to her swollen cock, which twitched violently against her stomach. “You’re becoming a fucking fantasy.” She took the nipple into her mouth, suckling hard, her teeth grazing the sensitive peak.

The dual sensations—the fearful churn in her stomach and the electric pull in her groin—left Evie dizzy. Clare’s mouth was demanding, her hands roaming over Evie’s ribs, her stomach, then closing around the base of her cock again. This time, both her hands were needed to form a loose ring. She began to stroke, a slow, worshipful pump that made the skin slide gloriously over the iron-hard core.

“I want it,” Clare muttered against Evie’s breast, her breath hot. “I want it inside me. I don’t care if it hurts.”

“Clare, last night you could barely—”

“Last night it was smaller.” Clare lifted her head, her eyes blazing with a reckless determination. “I’ve been stretched. I’m ready.” It was a lie, and they both knew it. It was the same furious, competitive need that had driven her on the rooftop, watching Sophie. She needed to conquer this, to prove her body could adapt, could take what this new Evie had to give.

She moved with a predatory grace, straddling Evie’s hips. The sheet fell away completely. In the dim light, Clare was a pale, sleek goddess, her own arousal already glistening on her inner thighs. She reached between her legs, positioning the broad, leaking head of Evie’s cock at her entrance.

She sank down.

A strangled, choked sound escaped her. It wasn’t a moan of pleasure; her face contorted, her jaw clenched so tight a muscle jumped in her cheek. She managed an inch, then two. Her body, swollen and tender from the night before, resisted with a fierceness that was almost violent.

“Fuck,” she gasped, her knuckles white where she braced them on Evie’s chest. “Oh fuck, fuck, fuck.”

Evie lay frozen beneath her, torn between the mind-blowing sensation of that searing, clutching heat and the horrifying sight of Clare’s pain. “Stop, Clare. You have to stop.”

“No.” The word was a brittle snap. She pushed down again, a brutal, grinding descent. A third inch disappeared inside her. A shudder wracked her frame. Sweat beaded on her upper lip. “I can… I can feel you… splitting me open.” Her cunt was stretched to a breathtaking, impossible diameter. The outer lips were pulled taut, gleaming and flushed. She was so tight around the embedded portion it felt like a ring of fire.

Clare tried to move, a tiny, experimental rock of her hips. Her breath hitched in a sob. It was too much. The barrier wasn’t just psychological or one of soreness; it was physical, anatomical. Evie was simply too large.

A tear, hot and sudden, traced a path through the sweat on Clare’s cheek. It was a tear of furious, humiliated frustration. She looked down at where their bodies joined, at the obscene, beautiful thickness stretching her, and a whimper broke from her throat. She was impossibly, devastatingly turned on, her clit swollen and throbbing, her inner muscles fluttering weakly around the invading presence, yet she was utterly incapable of taking what she so desperately wanted.

Her gaze lifted to Evie’s. The raw need in them was shadowed by a dawning, helpless realization. “I can’t,” she whispered, the admission a defeat.

The words hung in the silent, gray room. The truth of them was more intimate, more devastating, than any act of sex. Clare, always the conqueror, had met a summit her body could not climb. She collapsed forward, her forehead resting on Evie’s shoulder, her body shaking not with passion, but with a furious, thwarted grief. She was still impaled, painfully, on those few inches, a living monument to her own limitation.

Evie’s hands came up, hovering for a moment before settling on Clare’s trembling back. She could feel the rapid, rabbit-fast beat of Clare’s heart. Her own cock, still trapped in that agonizing, exquisite vise, throbbed with an urgency that felt grotesque in the face of Clare’s despair. The serum had given her the key to Clare’s deepest hunger, and in the same motion, had welded the lock shut.

Evie felt Clare’s tears, hot and silent, soaking into the skin of her shoulder. The weight of Clare’s defeat was a heavier burden than the monstrous cock still stretching her. “I wanted it,” Clare whispered, the words muffled and raw. “I wanted to take all of you.”

“I know,” Evie said, her own voice a rough scrape. Her hands moved from Clare’s back, sliding down the tense arc of her spine. One settled on the swell of Clare’s hip, the other dipped lower, through the damp thatch of blonde hair.

Clare flinched at the touch, a tiny, involuntary spasm. “Don’t. It’s pathetic.”

“It’s not.” Evie’s fingers found the slick, swollen knot of her clit, impossibly hard and fever-hot. Clare was so aroused it was a kind of agony. Evie touched her there, not with pity, but with a focused, steady pressure. She began to rub in slow, deliberate circles, her thumb moving over the hypersensitive nub.

“Evie…” Clare’s protest was weak, dissolving into a sharp gasp. Her hips twitched, a tiny, desperate thrust against Evie’s hand. The movement drove her an infinitesimal fraction deeper onto the thickness inside her, and she cried out, a mangled sound of pain and shocking pleasure. Her body was a live wire of conflicting signals—the searing stretch was a blinding border, but the direct, rhythmic stimulation on her clit was a relentless current coursing through it.

“Just feel it,” Evie murmured, increasing the pace of her thumb. She watched Clare’s face, twisted in a sublime sort of torment. “You’re so fucking wet. Your body wants it.” Her own cock pulsed inside that clenching, impossible heat, a deep, sympathetic echo.

Clare’s whimpers grew more frantic, her breath coming in short, punched-out bursts. Her hands scrabbled at Evie’s shoulders, nails biting in. The blockade of pain and size was still there, an undeniable, physical fact. But Evie’s fingers on her clit were building a wave that seemed destined to crest over it. Her internal muscles, so tight they trembled, began to flutter in a ragged, involuntary rhythm around the invading girth. It was the sensation of being so completely filled, so utterly claimed and stretched to her absolute limit, that finally unraveled her.

Her back arched violently, a strangled scream tearing from her throat. It wasn’t a graceful climax; it was a seizure of pure sensation, a brutal, convulsing release that slammed through her. Her cunt milked the few embedded inches in frantic, pulsing waves, a slick flood of her own release adding to the mess between them. She shook through it, her eyes squeezed shut, her body bowstring-tight for one endless moment before collapsing onto Evie’s chest, spent and shuddering.

For a long time, the only sounds were their mingled, ragged breathing and the distant hum of the city waking up. The gray light had brightened to a pale gold, illuminating the sweat-sheened planes of their bodies. Evie’s cock, still achingly hard and mostly unsated, remained lodged inside Clare’s slackened, twitching heat.

Clare finally shifted, a wince ghosting across her features as she lifted herself off, sliding free with a wet, soft sound. She rolled onto her back beside Evie, staring at the ceiling. “Well,” she breathed, her voice hollow. “That’s a problem.”

Evie didn’t answer. She looked at her own body, at the monstrous erection curving up from her pelvis, glistening with Clare’s juices. It looked like it belonged to someone else. Clare’s phone buzzed on the floor, piercing the silence. She didn’t move to get it. “That’ll be the office,” she said, flatly. “I should call in and let them know I'll be late. I can’t… walk right now.”

The clinical, logistical statement was more frightening than any cry of passion or pain. It was the sound of their new reality crashing into the old one. Evie swung her legs over the side of the bed, the weight between them a cumbersome anchor. She needed a shower. She needed to think. But first, she needed to move. Each step toward the bathroom was a clumsy, wide-legged gait, the throbbing in her groin a constant, aching reminder. Clare watched her go, her expression unreadable, a sheet pulled up to her chin like a shield.

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