A common problem among pricks and Uber-jocks. It occurs when they're actually so full of themselves they talk soo much shit that the only way to shut them up is to put some balls in thier mouth.
Freddy: "Yo Johnny the QB thought he was tough shit talking to my girlfriend the other day."
Bronson: "Really, dude what did you do?"
Freddy: "I gave him a good case of Ballsinyourmouthitis"
Bronson: "Sick dude, he's probably going to be too busy picking pubes out of his teeth to talk anymore shit for a while"