When a girl has gums (pertaining to the teeth) that are too large for her face to the point where they resemble a Great White sharks gums. Aka Miley Cyrus.
Bro1:Hey man what does Miley Cyrus have in-common with the shark from Jaws...
Bro2: I dunno.. I never thought about it..
Bro1: Bro, Miley-Mouth.
Bro2: What do you mean,"Miley-Mouth?"
Bro1: You know, where a girls gums resemble those of a Great White shark.. duh
Bro2: Oh.. like similar to the shark in Steven Spielberg's 1975 thriller; "Jaws?"
Bro1: Y.e.s. bro. Exactly.