Green’s Dictionary of Slang

chin music n.

[chin n.2 (1) + SE music]

1. conversation, chatter, talk, esp. defiant, aggressive, cheeky talk.

[UK]‘Bill Truck’ Man o’ War’s Man (1843) 92: Yon’s a blarney – mere claver and chin music – that gaed out at the ae lug as fast as it cam in at the ither.
[US]D. Crockett in Meine Crockett Almanacks (1955) 125: Says I, give us none of your chin music.
[US]‘Jonathan Slick’ High Life in N.Y. II 108: I thought [...] to give ’em a short specimen of Weathersfield chin music.
[US] in Journal of Discourses V 101: Whenever he attempts to amuse them with his chin-music, they expect that he will say something funny.
[US]Wkly Varieties (Boston, MA) 3 Sept. 4/3: Will the Chief of Police give this boy-policeman a little ‘ chin music’ in regard to his duty.
[US]North Amer. Rev. July 296: ‘Chin music’ we venture to call it.
[UK]Besant & Rice Golden Butterfly II 206: ‘I am not,’ he said, ‘going to orate. You did not come here, I guess, to hear me pay out chin music.’.
[US]World (N.Y.) 3 Aug. 3/1: They [...] kicked till the umpire assessed McKean $25 for too much ‘chin music’.
[UK]Sporting Times 22 Feb. 2/2: It transpired that we could have done without all this chin music.
[Aus]Truth (Sydney) 2 June 3/4: I called on my friend the Barber [...] to get my customary threepenn’orth of chin music.
[Aus]Sun. Times (Perth) 10 Jan. 4/5: He and Toby Barton were members of the same debating society at Sydney university [...] George took to chin-music as naturally as a duck to water.
[US]B. Fisher A. Mutt in Blackbeard Compilation (1977) 61: His keen intellect active brain and abnormal capacity for chin music.
[UK]‘Doss Chiderdoss’ ‘With Music’ Sporting Times 8 Jan. 1/3: She told three or four / Just what she thought about it, with music, I’m sure, / The descriptive sort known as chin music.
[US]S.F. Call 22 June 6/5: I should be havin’ t’anks instead o’ chin music.
[US]M.E. Smith Adventures of a Boomer Op. 60: If his chin music had been morse he’d had Barfield looking like a cadet in a ‘Ham Factory’.
[US]C. Sandburg People, Yes 90: I don’t believe a word you say but I love to listen [...] to your chin music.
[US]R.L. Bellem ‘Dead Man’s Shakedown’ in Dan Turner Detective Mar. [Internet] It gives us a chance to fling some chin music without interruption.
[US]P. Kendall Dict. Service Sl. n.p.: chin music . . . talking.
[US]B. Schulberg On the Waterfront (1964) 132: Knock off the chin music.
[UK](con. 1940s) G. Morrill Dark Sea Running 155: Knock off the chin-music, Navy.
[US]Seattle Central Community College On-Line News 5 Dec. [Internet] Did you know? [...] Other ‘chin’ expressions for loose lips include ‘chin-music’ (a noun meaning ‘idle talk, chatter’), ‘chinfest’ (another noun synonymous with ‘chat’), and ‘chin’ itself (which can be used either as a verb meaning ‘to chatter’ or a noun meaning ‘a chat’).
[UK]Guardian Sport 1 Mar. 22/3: Vaughan [...] confessed yesterday to knowing very little about Lawson, but expected the orchestration of ‘chin music’ to be no less intense.
[US]Mad mag. Aug. 38: Dubya’s good ol’ foreign policy chin music.

2. (US) promotional copy; persuasive writing.

[US]C.L. Cullen More Ex-Tank Tales 135: Some feller that’s a good ink slinger an’ thet kin spread good chin music on paper.

In phrases

jerk chin music (v.)

to gossip, to chatter; to speechify.

[US]‘Mark Twain’ Innocents at Home 332: The thing I’m now on is to roust out somebody to jerk a little chin-music for us.
[UK]Sporting Times 28 Mar. 1/4: When, at Bedford College, a she-woman jerks the classical chin music, the outrage is too awful.