So do you want:
1) "Herminie’s mistake?" (Fan fiction) (Mental)
Did Hermione really make such a big mistake with her temporal youth potion, or did someone add a little something to it? And what are the side effects? Could it have something to do with her loss of continence, and forced her to wear diapers (start with bed wetting and move on up), or her continual tempory child like behaviour and childish wims. Fortunately Ginny being a good friend, once she finds out starts looking after Hermione and the Christmas holidays come as a relief as there is virtually no one left at Hogwarts except her and Ginny, but is that a good thing? (Note this can involve Ginny having mental regression to but that your choice) (THE ONE YOU PICKED)
Or
2) "Babies don't need jobs" (Forced)
21 year old harry Goodman lives with his girlfriend, also 21, but harry has the problem that he cannot hold down a job for more than a week, so his girlfriend provides the income for all the things they own. As time goes by he starts to lose interest in getting job and decidedes to let his girlfriend (Emma) do the work, big mistake. (Note, do not spend time going to that, it was just a prologue) When Emma finds out she decides that there is only one sort of male that lives completely off a lady, and that is a baby. So she decides that if harry wants to live off her completely, then he must become her baby, and at his birthday (His twenty-first) she tells him her plans and introduces him to a party for a baby, harry of course tries to fight back, but as she not only has all the money in her name and she is also physically stronger than him, he is soon wearing diapers, what happens after that? (Note do not start the story at the end of the info, start it just around the time she finds out harry's plans)
3) "O Mr Sandman give me a dream, a horrible concoction like Diapers and cream" (Forced)
They say cheese gives you nightmares, but does milk? 17 year old Alex yeatman (Male), seems to be in a nightmare of no escape, in this world he is a baby, or rather he is still the same age but is treated like a baby, by everyone. But there is something else, why is it he seems fully awake if he is dreaming? Why does everything seem so real? And why can't he wake up?
4) "The plague" (Mental/later physical)
Jo king is just a normal ordinary every day, 29 year old woman, who is single and doesn't have any children and a few friends, but as time is going on she finds herself thinking more and more about babies, not just having a baby, but what it would be like if she was a baby, then the dreams start, all the same theme, she is either a baby or she dressed like a baby, then on night she wakes up and finds she has wet the bed, so she goes to see the doctor, who diagnosed her as having the new age regression virus, as such soon she won't even be able to look after herself, so which path know?
5) "O Sister (or is it brother now?)" (Physical {but not in the way you would think})
16 year old Dan gardener and his seven year old sister have been fighting for years, and know Rebecca has got the upper hand, you don't know where she got it but somehow she got her hands on the device, and know everyone thinks she is you and you are her, not only that but your clothes have changed to hers, you positions have changed in pictures, you reflection has changed to hers (but your body is still the same, it’s just an effect of the device), your abilities have swapped, Their friends haven't swapped but they think they are each other’s friends IE Dan’s friends are still his friends but they think they are seven year old girls (this includes Dan’s girlfriend), and only Dan and Rebecca remember before and see their friends as they really are, is there any way out of this nightmare?