Wiktionary
chin music
n. (context baseball informal English) A fastball thrown near the batter's chin, often to set up a subsequent pitch thrown low and outside.
WordNet
Wikipedia
Chin music
Chin music is a slang term with several different meanings.
Usage examples of "chin music".
They are too tired to discuss recent events with him now, but they're ensuring that he won't slip away before they have a chance to make a lot of chin music with him later.
Thereupon a young sprig, from the East, blustered like a Shanghai rooster, and began to sass the conductor with his chin music.