Make sure that all bottom parts are thoroughly powdered before you begin. You'll also want to prepare by standing on a towel. Then, take your diaper (or panties) and completely fill it with baby powder. Cover the surfaces until you are sure they can't be covered anymore, then put the diaper (or underwear) on and shake some more powder in around your bottom. Take the cap off the bottle if necessary to get a really excessive amount. You may wish to wear pants today, or put on plastic panties or tights, in which case you will only smell of talc. The humiliation enters if you don't, because if you've used enough, a white powder will be sifting out of your crotch.