When you use a turd as a masturbation device. Specifically, you rub your
penis back and forwards inside a piece of shit.
Alternatively, fucking a black
girl (or guy, but only if you're the giver). This is a
racist extention of the above definition.
Person 1: "I poowanked last
night."
Person 2: "You took a dump and
stuck your cock in it?"
Person 1: "Nah, I fucked a black
girl."