Thirteen's a fun age. Time when life's changing so much, when you start experimenting...you know, with stuff." I would be old enough to do sports and stuff, but young enough where I don't have too many responsibilities. It might be fun to experience the early days of puberty again," said Mike after some thought.
"Okay..."
Jeff entered in 13 for Mike's new age and hit enter.
"Whoa..." said Mike a few seconds after Jeff had hit the accept button.
"What is it?"
I just felt a warm... pleasurable... pulse through my body... d-damn... there it is again..." said Mike, grabbing onto the back of Jeff's chair. Jeff rose and looked at Mike. For a man in his late thirties, he wasn't half bad looking. He was clearly a thicker man who'd clearly let himself go a few years ago and was now a bit husky in addition to his hulk. However as Jeff stared, his father's slight pouch of a belly seemed to be shrinking, and the thickness to his body seemed to slowly be decreasing, like a balloon slowly deflating all at once. The pulses seemed to gain in intensity and were likely waves of youth returning to Mike. Already, his dad Jeff estimated looked closer to his early thirties now than he had a few moments ago. With a third waves of pleasure, gone was the pouch, and the shorts that had been on the tighter side now looked a little loose, if not sliding down a bit. His shirt seemed to be filled out a bit more, as Jeff's dad became younger and buffer.
However the transformation was far from over, and the waves of pleasure seemed to intensify as he re-entered his twenties and started looking more and more like a young adult rather than a father of three. Body hair was beginning to thin a bit as second puberty undid itself, not leaving him without any hair, but far less than he had had moments ago. The beard his dad had acquired over the years was now close-trimmed and far less bushy looking. Muscles bulged while his body's thickness thinned out, soon a rather athletic looking young college stud was standing in Jeff's room.
"My head's starting to ache a bit..." complained Mike as he placed his hands up on his temples as his muscles deflated even more dramatically now and he dropped an inch or two as he left his twenties, his beard sank back into his face and his body hair seemed to shrink to just some hair on his arms, his legs, and a bit of scruff on his face that was all quickly lightening, shrinking, softening, and turning to peach fuzz.
The next wave apparently was the most pleasurable as Mike moaned out in what sounded like pure ecstasy as the now teenage Mike lost all muscular definition to become a bean pole with overly large hands and feet for a moment before his voice cracked and the growth spurt... uhhh shrink spurt? Yeah, shrink spurt. ... the shrink spurt caused Mike to be sent straight from being a teenager to a preteen. At this point, Mike's adult clothes which had more or less remained on his body, despite sagging or stretching as he'd changed his workout routine over the years, suddenly seemed to bag on him. His adult shorts dropped to the floor, as his now stretched out shirt hung off his smaller frame.
"Hey Mikey, you good?" asked Jeff, the name Mikey just feeling natural to call his little dad now.
Without missing a beat, Mikey sat up with a big grin. "Yep Jeff! This is the best thing that ever happened to me!"