The feeling left in the mouth and throat after a heavy nights drinking. Impossible to brush out, eat out, sleep out or get rid of in any way.
Rob: Alright Olli, what you get up to last night.
Olli: Got fucking rat assed on vodka at some party then like passed out on some girls bed.
Rob: Sounds heavy
Olli: Yeah man I have serious rat mouth right about now
any person that fakes in your face and go behind your back tell all kinds of lies and make up rumors about a person.
cIARA TOWNES IS A RAT MOUTH SHE GOES AROUND TOWN CLAIM COOL WITH DIFFERENT PEOPLE AND THEN SITTING UP GOSSIPING RUMORS ABOUT THEM,CLAIMING SHE THE REAL DEAL.