They watch the effects of Monica's cum.

"Mom? My... owww, my chest feels so tight!" Adam squeaked as he shot up, eyes fixed on his reddening breasts. His heart was racing, and with every rapid beat, more blood was pumped into his boobs - they felt as if they would burst from the pressure.

"Oh baby, oh no, that's my fault, I'm so sorry," his mother babbled, reaching for Adam's shoulder, but Adam twitched and arched his back, thrusting out his tits before him, his diamond-hard nipples brushing against her palm.

"Ngaaooh," Adam groaned - it felt as if the hard little nub was wired directly into the pleasure center of his brain, little sparks were flying in front of his eyes, his jaw gaping open. All he could do was keep breathing, each breath a lewd gasp. Monica pulled her hands to her chest, wringing them in futile worry. There was nothing she could do to help her poor baby!

Adam meanwhile was lost to the world, the mix of pleasure and pain in his chest all-encompassing. Just before the pressure became unbearable, a sudden feeling of release spread through Adam's tits. Before his eyes, they started to take on mass. With every quick, labored breath, more titflesh grew in, the burgeoning boobs slowly reaching a size where they began to droop.

"No, no, no, I... uuunnghh... This can't be... haaahhh... happening..." Adam pleaded, but it was all for naught - his breasts showed no sign of stopping. Tears started welling up in his eyes. Why was this happening to him? He wasn't gay! At no time in his life had he ever lusted after cock, but now his desire for a dick - his own mother's even - had lead to this. It just wasn't fair. And why did it feel so GOOD?!

Monica meanwhile struggled with a similar conundrum: The sight of her little baby growing sizeable boobs and moaning in a mix of pleasure and horror was doing strange things to her crotch. Her member tingled and lurched - but why? Her poor son was in distress, why was this so exciting for her? She started chewing on her lower lip to keep from moaning out loud, but one of her hands started to rub her tits subconsciously.

(Author's commentary: Vote for tit size is now closed. DD got two votes, rest only one, so DD it is.)