A woman who pisses on your chest immediately after fucking her brains out. It has not yet been determined the exact nature behind this phenomena but one must assume it is simply an act of territorial procedure. The pissing can also be accompanied by some silent farting which in most cases is just plain fucking disgusting.
Steve: Hey man the funniest thing happened. I was just finishing up plowing your mom for a good 17 minutes when the crazy bitch got up, crouched over top of me, and starting pissing.
Jim: Aw sick dude... my mom's a pisser!?!?