Chin music
Chin music is a slang term with several different meanings.
In American slang, chin music is a term for idle talk. It dates back at least a century: "There's too much chin music an' too little fightin' in this war, anyhow" is a quote from Stephen Crane's 1895 novel The Red Badge of Courage. It can alternatively be used as a euphemism for punching someone in the jaw.