Oh no we swapped genders

The last of the shifting finished with a low, rolling pulse that left both of you shaking on the cold metal floor. MJ’s new body settled into its final shape broad shoulders, thick arms, a heavy cock hanging between his thighs that had already gone fully hard, flushed dark and leaking at the tip. He stared down at it like he couldn’t believe it was his, one big hand wrapping around the base on instinct. A rough sound left his throat.

You felt your own body lock into place at the same time. The new breasts were full and heavy, nipples tight and so sensitive that the ruined fabric of your shirt dragging across them made you whimper. Between your legs everything was soft, wet, and aching. Every small movement sent a sharp pulse of heat straight through your core. The hormones hit like a second wave of the gas thick, dizzying, impossible to ignore. Your skin felt too hot. Your pulse thudded between your thighs. You could smell him, clean sweat and something sharper underneath, and the scent alone made your hips shift.

MJ looked up. His eyes were dark, pupils still wide. He moved before either of you spoke. One second he was on his knees; the next he was over you, big hands tearing what was left of your shirt open. The cool air hit your bare breasts and you arched hard, a broken sound catching in your throat. He stripped the rest of your clothes with the same rough urgency, then shoved his own ruined hoodie and jeans aside. His cock slapped heavy against your stomach when he settled between your legs.

“Can’t ” His voice was deep, strained. “Can’t think. Need ”

You didn’t answer. Your legs fell open on their own. He lined himself up with one shaky hand and pushed in. The stretch was immediate and thick. You cried out, nails digging into his shoulders as he sank deeper, inch by inch, until his hips met yours and he was buried to the hilt. The feeling was overwhelming full, hot, every sensitive place inside you lighting up at once. Your new breasts pressed against his chest with every breath. When he pulled back and thrust in again, hard, the slap of skin echoed in the metal room.

He set a brutal pace right away. No hesitation, no talking. Just the wet sound of his cock driving into your pussy, the low grunts leaving his throat, the way your body clenched around him every time he bottomed out. Your breasts bounced with each thrust. He dropped his head and sucked one nipple into his mouth, tongue rough, and the sensation shot straight to where he was fucking you. You wrapped your legs around his waist and rocked up to meet him, heels digging into the small of his back. Every movement made the heavy weight of your ass shift against the floor. You were both too sensitive, too new, the hormones turning every touch into something sharp and necessary.

He fucked you like he couldn’t stop. Deep, fast strokes that made your whole body jolt. One of his hands slid under you, gripping the curve of your ass, lifting you so he could drive in harder. You felt the thick head of his cock drag over that perfect spot inside you on every thrust. Your orgasm hit fast and hard your pussy clamping down around him, a high, broken moan tearing out of your throat as you came. He didn’t slow down. He kept thrusting through it, chasing his own release, the wet sounds getting louder as your body got slicker.

“Gonna” he gritted out against your neck. “Fuck, Peter”

He buried himself deep and came with a rough groan, cock pulsing as he spilled inside you. The heat of it filled you. He stayed there, hips jerking in small aftershocks, both of you breathing hard. Your breasts were flushed and aching. His cock was still hard enough that when he shifted you felt it move. Neither of you pulled apart. The hormones were still screaming. Your body clenched around him again, greedy, and he answered with another slow, deep thrust.

You both knew, somewhere under the haze, that the changes weren’t finished settling. A full day before your bodies locked in completely. Until then the new hormones ran everything. Peter could get pregnant after today. MJ couldn’t get anyone pregnant until tomorrow. Right now none of that mattered. He was already moving again, cock sliding through the mess he’d just made, and you were already rolling your hips to take him deeper, the two of you fucking on the cold floor like nothing else existed while the last of the lab’s distant voices faded down the corridor.