well, when your tama is an adult, you can use the suit on your tama. what happens is that your tamagotchi wears it, after that it looks like another character...hohotchi. it stays on the tama until it sleeps, unless if you change the time to bed time. I suggest you change the time and not put it on when it's a parent because when the parent leaves you'll lose the costume, and if you don't take it off before it's bedtime you'll lose the costume. I hoped that helped!
-mimtichirules
p.s my tama's a mimitchi!