1- obviously you can't wear anything else than diaper, and toilets are off limits (including for mess if it's in your limits) and have to use them everytime you need. Babies don't hold anything.
2- No grown up clothes at home, you have to wear childish clothings all the time. If you have to go out you may wear somes grown up clothes over an onesie or baby dress, but only short enough to reveal what's under when you bend. You also have to follow the first rule when you are out.
3- Extending the two first rules, you always have to use baby items which mean pacifier always in your mouth unless you are eating or outside (must be somewhere with you in this case, like pocket or somewhere else), never drinking out of anything else than baby bottle and you have to eat with baby forks and knifes, or with your bare hands.
4 (optionnal) - If you have baby mittaines, wear them all the time when you are at home, only remove them when you can't do otherwise like when you are eating or brushing your teeths.
5 - Crawl as much as you can. You can stand up if you really have to but you can't walk. Of course this one is also when you are at home.
6 - No grown up untertainment at all, you can only watch/read movies/shows/books for babies no matter the situation.
7- Bedtime is 8pm at the later, don't forget your teddy bear and your paci
8 - At least one time this week, you have to be brave enough to humiliate yourself and ask someone where you can change your diaper. Of course you have to do it then.
9 - Can't believe I didn't say it earlier, you are not allowed to eat anything else than baby food.