1. a girl with the face that you can tell that is a slut..with like make up on it
2.a plain old skanky slut with a shit load of make up on and pimples because she never takes her make up off
"What a slut face"
"Woah just by looking at her face you can tell she's a slut"
The face you make during a song you really like, and you're dancing really slutty to. It probably involves pouting of the lips in an "o" like fashion, sticking your ass out and grinding like a cat in heat on the nearest person.
The girls have their slutfaces on as they dance to "My Humps".