Both partners play a joke on the other that quickly gets out of hand, the minor growth quickly escalates into major unwanted growth resulting in them using their new features on each other as "punishment". She gets breast, ass and hips while he gets cock and balls, some mocking and horny interactions.
Wet sounds and quiet grunting filled the living room as the two occupants glared at each other from their respective armchairs. Both of them were panting hard, cheeks flushed with arousal, but anger burned behind their eyes.
"God, you f-fucking asshole! MMF! L-look at what you did to—holy fuck—my f-fat fucking t-tits! D-do you have any idea h-how much—aahhn!—how m-much this fucking b-bra cost?! And n-now it's r-ruined!"
Lauren did her best to be angry but it was tough to properly convey her fury while she was actively touching herself. The movement of her arm, resting against the side of her colossal tits, made them wobble and slosh, bouncing back and forth inside her overworked bra. The arms of the chair under her were pushed outward slightly by the wide hips stuffed into it and her whole body was lifted by the plump ass sinking into the cushion. Her hand writhed between her thick thighs, sending pleasure through her entire body. She narrowed her eyes at the person sitting opposite her.
"Yeah, b-but I bet you fucking like that, h-huh? Knowing that this b-body you gave me is t-too big to w-wear clothes! Turns you on to see how you fucking ruined my life! T-turned me into a f-fucking porndoll!"
Between huffs and moans, Ryan let out a wry scoff.
"R-ruined your l-life?! J-just look at w-what—oh jesus fuck—you d-did to me!"
As he glared back at his girlfriend, Ryan's hands never stopped moving. They slid up and down the length of his cock, all three and a half feet of it. It was thick enough that he couldn't fully close his hands around it and precum gushed from the tip, coating his cock in a glossy sheen. Between his legs sat a pair of swollen, heavy balls that churned and sched and begged for release. A wave of arousal struck him and he bucked his hips, forcing his cock upward between his hands. Tilting his head back just made his moans even louder. He did his best to press on.
"I c-can barely w-walk with this thing! In the r-rare fucking moments when it's s-soft, it hangs p-past my fucking knees! If I don't c-cum—shitshitshitfuuuuck—If I d-don't cum at l-least three t-times I day, I go f-fucking insane! And then I c-cum a fucking ocean!"
Despite herself, Lauren moaned, the thought of her man unleashing that much fucking cum overwhelming her. "Th-then do it! Quit f-fucking around and c-cum! You're t-too fucking big to actually fuck me! Or anyone! S-so you might as well just j-jerk off that gigantic fucking cock!"
Another wave of arousal made Ryan's balls twitch. Fuck, he was close. "Of c-course you want me to d-do that you f-fucking cumslut! You want every l-last drop of my ballsludge! You wanted to be p-painted in it! You w-want my thick, h-hot cum all over your h-huge fucking p-porntits! You w-want me to b-breed your f-fucking titpussy!"
"You... Y-you... Oh, fuck, FUCK, I'm gonna— AHHHNNN!!"
Tension gripped Lauren's body as an orgasm ripped through her. Her thighs and ass clenched, lifting off of the chair as she shoved her tit against her face. It barely muffled the intense moans that poured out of her, humping the air and thrusting her hips. Milk arced from her nipples, spraying across the room in her lewd display.
Finally, her body relaxed. She collapsed back into the chair, panting and sweating, heart pounding and chest heaving. "Fuh... Fuck...."
Across from her, Ryan gripped the arms of the chair as hard as he could. Slow, deep breaths held his concentration and, gradually, his cock softened. Precum poured from the tip as it did, slowly coming to rest draped over his humongous balls. His cock twitched but it stayed soft and, gradually, Ryan relaxed. "H-hah! Guess I win! Th-that's another cup size for you!"
Lauren groaned. She hated losing. She hated growing. But, most of all, she hated how right he was and she hated the fact that she wasn't plastered, head to toe, in his cum. Next time, though. Next time, it'd be her win.