Someone who gives a lot of Oral Sex.
Also can be used for someone that is overly talkative.
Can be used as an offensive 2 word Attack. Or as a Defensive 2 word Come-Back.
Did you hear about how she is a jaw slut?
Tonights date will be awesome, I heard she is a jaw slut.
Dude, you are a major jaw slut. Shut up for once!