A sex act invented in a thought experiment by two stoned virgins and popularized via Urban Dictionary. No human being, alive or dead, has ever actually performed this sex act, but it has attained a degree of cultural currency through shock value.
Stoner 1: Dude... like... what if you, like, went to titty-bang a girl, but then totally took a dump and then sat in it?
Stoner 2: Baahahaha hahaha haha ha ha hahaha ha we should call that a Cleveland steamer!
Stoner 1: Uh... why?
Stoner 2: Because, like, the poop would steam if it's cold out... and it's like Cleveland!
Stoner 1: Hahahaha yeah totally. This is going to be the best Urban Dictionary sex act ever.