For a diaper punishment keep them in a diaper
? A diaper as a punishment ? Umm... Throw it at them ? Jk ... Are you trying to potty train a child or something ? If so let them wear underwear over a diaper get them to like how underwear looks, take them to the bathroom a lot even if they say they don't have to go just get them used to it, when they get good at telling you they have to go to the bathroom try just wearing the underwear, if they have accidents take them to the bathroom and tell them you will get rid of their (( dora or spider man )) underwear and go back to diapers if they have accidents. But you have to do your part and remind them as hard as it is to believe they forget. So just ask them at random moments if they need to use the bathroom. And never laugh when the have accidents that gets them attention and they'll think its funny to do that all the time. But don't yell at them if they have accidents be firm, but not aggressive.