jaw-jack, v. — Green’s Dictionary of Slang

jaw-jack v.

[US black pron. of jaw-jerking/jerking off, i.e. ‘verbal masturbation’]

(US black) to talk excessively, loudly or inconsequentially.

1962		in B. Jackson In the Life (1972) 163: And I’m sitting up here jawjacking with this other tramp.
1971		T. Whitmore Memphis-Nam-Sweden 87: We was always jaw-jacking about whose outfit was better. [Ibid.] 113: The white dude in front of me was jawjacking with the guy in back of me.
1992		D. Burke Street Talk 2 34: Ev’ry time I tried jaw jackin’ with Miss Thang, she got so frosted that I fin’lly jus’ folded.