Big enough to beat his mother on size.

As Adam's boobs packed on more and more jiggle, the pleasure radiating out from them intensified. His nipples could have cut glass, and his pussy was so wet his juices were drooling through his soaked pajamas.

"No, please, no, don't grow, nnnggooooh, god," Adam moaned, but the lust was already worming its way into his brain and his protests were growing weaker and weaker. There was nothing he could do anyways, so why not make the best out of a bad situation? It did feel pretty awesome... No! That wasn't him, that was the pills talking! He couldn't change more, he wouldn't! Adam wrapped his arms around his midriff tightly so they wouldn't stray to somewhere more dangerous.

But this had an effect he hadn't thought of - Adam's upper arms smooshed together his swelling breasts, giving his mother a mesmerizing display of his expanding boobs. They already bulged over his biceps and filled out the front of his pajamas nicely, straining against the fabric, but he wasn't done growing. Already he had reached his mother's size, but it looked like he would leave Monica in the dust.

Somehow, the idea of her baby having bigger tits then her immensely excited Monica. The distracted movements of her hands on her tits grew more insistent, her moans louder, and suddenly, her currently unattended dick exploded. She'd been incredibly close to cumming under the shower and the sight of twitching, moaning body proved to much to her; glob after glob of thick spunk fired from her lurching meatcannon, splattering all over Adam's pajama top and burgeoning bust. The smell hit his nostrils and suddenly, all his fears and worries were gone. Lying down on his back, he jammed both hands in his pyjama bottoms and began rubbing his pussy and clit greedily.

"God yes, so goooood!" Adam squealed, his tits settling on his chest like a pair of big, fluffy pancakes, drooping over the sides of his rib cage bit by bit. He closed his eyes in bliss, squelching sounds emanating from his crotch. Adam heard his mother moving, but was too engrossed in his masturbation to react. He only opened his eyes when he felt her straddling his torso, pinning his arms to his sides and pressing together his still swelling tits. Monica's angry purple helmet was inches from his face - the veiny rod itself was still rock-hard and drooling pre-cum. Staring at her cock, Adam's pussy was forgotten for the moment.

"Oooh, sweetie, you look so hot... can mommy fuck your tits?" Monica pleaded, eyes full of lust, hands grabbing her cock by the base.

Adam nodded his head, breath catching in his throat. His mother slipped up his pajama top, laying his boobs bare and prompting a sultry moan from Adam. Neither of them cared right now that a manly voice should not produce sultry sounds, so Monica grabbed Adam's breasts by the sides, feeling the soft flesh bulge through her fingers and slightly jiggled them, marveling at the boobquake.

"Nnaaoooh," Adam moaned, throwing his head back and arching his back. He attacked his pussy with renewed vigor, sounds of pleasure filling the air that only grew louder when Monica slid her cum- and spit-slicked cock inside her sons expanding cleavage. The shaft and head of Monica's cock rubbing against his sensitive tits felt marvelous.

"Mmmmnnhh, it's so soft, Adam," his mother cooed and began slowly bucking her hips into his bust, making Adam's tits jiggle and quake. They were already big enough to almost fully take her length and were slowly approaching the size of his head. While they seemed to slow their growth, this did not keep Monica from increasing the speed of her thrusts, Adam's cleavage slick with her pre.

"Ah! Yes, mom... oooh, fuck my titties," he squealed, his mounting lust drowning out all rational thought. Adam looked up at his mother's flushed face and smiled at her lewd look: Her eyes halflidded, lips forming a little 'O' of pleasure. The fact that he was giving Monica so much pleasure seemed to travel right into his snatch, juices spurting out and soaking his pajamas even more. Adam's fingers slipped inside, thumbs dancing over his clit. The combined pleasure from his cunt and tits made him dizzy and his eyes rolled up in his head, eyelids fluttering.

"You like that, baby? You like mommy's cock?"

"Nnnh... Yeah - ah! Fuck them harder... ooooh, touch my nipples..."

"Of course, sweetie... Hmmmh, mommy is gonna make you feel gooood."

Monica slid her hands from the side of Adam's tits towards their middle so she could reach his throbbing nipples with her thumbs and began flicking them gently.

"Hnnaaaah! God, yes! I'm almost ther-- Aaaah! YEEAH!" With a triumphant scream, Adam climaxed, his pussy twitching around his fingers, his back arching so hard that he lifted Monica in the air. His mother sensed her own orgasm approaching and increased the speed of her thrusts, each impact of her hips sending shockwaves through Adam's tits, the friction from her cock prolonging his orgasm.

"Ah! Ah! Ah! Too much, too good, fuck MEEE!"

"Oh god, Adam! This is so hot, you're... gonna... make... mommy... CUM!"

The last words were accentuated by forceful thrusts that slapped into Adam's underboob, and then Monica unloaded into his cleavage. The first powerful shots spurted out from the top of his breasts, splattering over Adam's face and partly landing in his mouth. He immediately stuck his tongue out to catch more of the salty goodness and was rewarded with a few more spurts landing on his tongue. Swallowing noisily, he slowly came down from his orgasmic high.

Once his senses returned to him, he felt as if he'd been doused with ice water. Not only did he have sex with his mother again, but he'd swallowed another dose of her cum. Who knew what effects it would have?!

Author's comment: What should we grow this time? Tits, ass, thighs or all? Let me know in the comments, simple majority wins.