Rumpstick has to meanings one a girls ass after being beat by a stick and for a guy inbetween his butt and dick being beat
friend one: Damnit! they beated my rumbstick fucking hard last night!
friend two: Dude i told you to break up with them they are goin to kill you.
friend three: Dude if your get rid of them can i have them?
friend one: You fucking kinky whore!