shut up war
When two kids get mad at each other and start telling each other to shut up. There's also "you're gay" wars too.
Example:
Me: Look at them; they're having a shut up war. Heh.
Kid 1: Shut up!
Kid 2: No, you shut up!
Kid 1: No, you shut up!
Kid 2: No, you shut up!
Me: Look at them; they're having a shut up war. Heh.
Kid 1: Shut up!
Kid 2: No, you shut up!
Kid 1: No, you shut up!
Kid 2: No, you shut up!