Stank: The quality of being whorish and/or trashy or the appearance of bearing said quality.
Ass: Term for donkey, the butt, or individual who is mean for no reason.
Put it together and you get someone from Shittsburgh.
Shittsburgh (Pittsburgh) is a stank ass city that spends millions of federal tax dollars on internetadvertisements so everyone thinks it is a nice place, when anyone from the outside knows it is not.
A girl (or guy) who runs around with everyone and thinks they're hot shit, when realistically they're just someone who's hit it with everyone and their brother. In summary, your everyday whore.