You get in the shower and start the washing process. You get to the part where you soap up your vag (or for guys, ass) and you soap and soap and soap it up some more until it's nice and sudsy. Then you move on to washing your hair or shaving your armpits or something, leaving your soapy crotch to be rinsed out when you're done the other cleaning processes. Then you finish and you step out of the shower and start to happily dry yourself off until you realize your crotch is still totally full of soap because you're a stupid retard and forgot to rinse it out. Then you have to go back in the shower (sometimes this proceedure can be done at the sink aswell) and rinse the crotch (or ass) suds away.
Or it's even worse when you're in the shower and you suddenly realize you have to take a big shit, so you have to get out the the shower and sit on the toilet and because your ass is wet, you start slipping all over the seat.
Or even worse when you're finished showering and you're all sqeaky clean and THEN you feel a huge shit coming on, and you got and take that shit and it totally ruins that fresh out of the shower feeling.