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."
The act of giving someone a "Thug Nafty In Yo Mouf" is as follows:
The man is receiving oral sex, then proceeds to urinate AND ejaculate into the female's mouth. After he is done, he looks down at the dumb whore and says "I just 'Thug Naftied in yo mouf bitch! Now go make me a damn sandwich"
"HeyLisa, if you come over tonight, I'll give you a Thug Nafty In Yo Mouf."
What happens when someone is served an open palmed disrespect, often utilizing a tool. Is seen as a deserved act of revenge after a period of humilation.
In that movie Wanted, the main character slapped the fuck out yo mouf when he bashed his cheating best friend with that keyboard. It said, "Fuck You"
A joke,in where the desired result is to get the victim to answer the question, allowing you to follow up with "D's (dicks)in yo mouf (mouth)!". The question mostly asked is "whats your favorite number?" or "whats you favorite color?"
joker--"HeyAngela whats your favorite color?"
angela--"moldy green"
joker--"D's in yo mouf!!"
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.
FRIEND A: "Did you just take a stealthie of me?"
FRIEND B (turning phone around): "no I was just using snapchat's new filter, see?"