(Original author here: I am embarrassed to admit that my first attempt at this story branch was a bit rushed and lacked a lot in some key areas. While I feel like this is in bad form, I have rewritten the branch from here.)
Madame Illusia began to work her magic as Monica bent down in front of Jason and placed the head of his cock against her pussy lips. “Watch me, Damon,” she commanded. “Watch this teenager take your cock and girl away. Watch as- Ooh! OOH!” Her voice was already husky from the magic, but as Jason grabbed ahold of her ass and began to push into her, the noises in her throat became more guttural and wanton. “Fuck yes, fuck yes, fuck yes!” Monica’s tongue spilled out from between her plump lips and her eyes rolled back in her head. Jason bent down to grab at her new pillowy tits and was fucking away like a jackhammer.
Damon grabbed onto his cock, already forgetting that Madame Illusia was working double-time to trade away his years to Monica and his cock to Jason. He worked it back and forth in his palm, feeling like he was getting close to the edge of orgasm as he watched Monica’s arms give out and her ass kick up into the air as Jason railed her from behind. But the climax never came as his hand seemed to grow too large for his shrinking prick. “Uh, Monica…” His fingers grew smaller along with his shaft and the hairs on his arm began to recede. He felt the stage floor getting closer and his girlfriend appearing to get larger as he shrunk down. The cold feeling in his veins was now tinged with fear, but he continued to stroke away - too aroused, too humiliated. He was watching his sexy MILF girlfriend, the one he used to be older than, get fucked by a kid who was… older than him now. He felt an orgasm building in his balls, but he just couldn’t get himself over the edge and he frantically pulled at his hairless dick, now only a few inches long.
“Don’t stop, don---- oooooh ooooooh don’t stop, baby.” Inside of her, Jason’s cock grew larger and thicker as it stole away Damon’s size. Monica’s dark black hair had grown lighter as it encircled her head messily as she slammed her ass back on the teenager’s massive tool. Her heavy breasts now pitched back and forth as she was used by him, her nipples growing darker as they pitched up and down shamelessly. Monica planted her palms on the stage and locked her legs up, looking like an animal in heat while Jason worked his new cock in and out of her. Every time it came out, it looked to have grown thicker and longer - more manly, too, with thick tufts of hair and prominent veins. Monica looked at Damon through a haze of ecstasy while her body was wracked with what was likely her second orgasm already.
The changes now were obvious and shocking. There was no hair framing Damon’s cock anymore and he had grown shorter by several feet. From where Monica bent low to the ground, she could make eye contact with the little boy who was slipping through his teen years. He was pale and scrawny, lacking the muscles and hair that she had come to love over their time together. His once strong jawline had grown soft and a little doughy. Monica couldn’t help but laugh, knowing that Damon had just turned himself into a child just so he could watch her get fucked by someone who knew what they were doing. Hell, Jason didn’t even know what he was doing and he was putting on a damn fine show in her insides. Damon tried to cry out to Monica again as he held what was left of his cock between his thumb and forefinger and was shocked by how high pitched his voice was. “Monica! My cock!” All that remained of the once older man’s dick was a bald nub that didn’t even look like it could get hard any more. There was still a chance… maybe an inch and a half left before it was all gone.
Arms having given out, Monica was now panting and drooling with her face on the ground as Jason held on to her hips and pounded away at her. His cock pulled out farther than it had before, and was nearly as big around as a soda can. His dark member would have had trouble fitting into Monica’s pussy if the woman wasn’t so aroused by the changes. The stage was glistening with her juices. “Fuckin’ come inside me, baby. I don’t care. Just don’t stop.” Monica’s eyes rolled lazily over to Damon who was still trying to work his baby cock between his fingers. He was a hairless little boy now, save for the mop of brown hair atop his head. Gone were the muscles that used to hold Monica tight. Gone was the cock that Monica used to happily slide down her throat. Even those once serious eyes were now large pools of innocence. “Mmm… yeah, that’s enough,” she purred. Struggling to her elbows, she pulled herself up and Jason’s cock popped out of her as the teen fell back, marveling at the size of it. I looked to be almost as large as his forearm. Jason made a soft complaint about not coming yet, but Monica shushed him with a look. The woman hefted one of her new huge tits with hand and let the other roam across her new thick thighs. Her once proud thigh gap was long gone, but she couldn’t say she was disappointed in the outcome. The well-maintained landing strip that led to paradise was a natural looking bush that did little to hide the swollen pussy within. A stream of cunt juice led down her thick thighs, around her calves, past her ankles, and pooled in the crevasses of her feet.
“How old are we now?” she asked Stephan, ignoring the frantic attempts at masturbation from Damon. His little cock just didn’t seem up to the task. His high-pitch squeals reminded Monica of middle schoolers seeing a dirty magazine for the first time. She smirked and began to touch herself, knowing she was the object of the boy’s desire.
“Damon over there is 12 now, while you are 42. A full eighteen years were exchanged between you two.”
Monica looked at Damon with a mixture of pity and superiority. She twitched as her fingers brought her closer to another orgasm. “Well, Damon, what say we…?”