Kyle frowned and tugged at the diaper. "I don't think I want to play this game."
Samantha giggled again. "Oh, it's no game. That diaper is magical. Take a look at yourself. I bet you aren't more than 12 now."
"Huh!?" Kyle jumped off the bed and realized he was already way shorter than the girl. He ran over to a mirror hanging on the wall and gasped when he saw himself. Even more age had vanished, and the ten year-old version of himslef kept shrinking as he looked at his reflection. He recognized the gap-toothed 8 year-old from his second grade photo. "No! Tham! Make it thstop!"
The awful lisp got worse as he turned 6, then 5. Samantha came up behind him with a big grin and hoisted him up easily as he regressed to a 4 year-old. "Awwwww. You're gonna be such a cute little baby boy."
"No no no no no!" Words were fading from Kyle's mind and he started to cry. "Pwease. Not baby! Not be baby!" But even as he struggled to get those words out he could see that she was already holding a toddler no more than 2 years old.
She shifted him in her arms, cradling him lovingly. Kyle was terrified, clenching his fists and struggling to keep hold of the knowledge and memories that were fading away. She poked his tummy gently and broke his concentration, and he giggled.
There was movement to the side, and he looked over to see the reflection of Samantha holding a cute little 8-10 month-old baby boy in a diaper. The baby stuffed a fist in its mouth and gurgled, looking very happy. Kyle dimly realized he was sucking on his fingers and feeling curious and content. He remembered being older, but it was so much easier to just relax and be a baby.