Fuck your mouth, otherwise said as "fuck yo mouf" is the reply to a "slam" or a "burn." Generally stated after a person says something offensive, wrong, or a lie.
Man 1: "Yo, my hommie just rolled up on some bitches and hit it hard last night."
Man 2: "Man, that was my sister. Fuck yo mouf!"
Man 2: "Man, that was my sister. Fuck yo mouf!"
by CGPierce May 01, 2008