Green’s Dictionary of Slang

(US) awkward, uneven, foolish; also adv.

1957		in Merriam-Webster’s Collegiate Dict. (1998).
1988		‘Victoria Parker’ Incest Schoolgirls 🌐 The girls slugged on his prick with herky-jerky strokes, amazed by his thick outpouring.
1995		J. Stahl Permanent Midnight 252: Legions of herky-jerk, piss-legged mental defectives tweaking down the street.
1999		J. Ridley Everybody Smokes in Hell 48: The result was a herky-jerky dance by Paris from the backroom into the main room, a shelf knocked over along the way.
2005		J. Stahl I, Fatty 100: Out flies Chaplin [...] doing that herky-jerk shuffle that turned into his trademark.
2022		J. Hannaham Didn’t Nobody Give a Shit 47: [T]he uptown and downtown sides [i.e. of the subway] were still herky-jerky.
2023		(con. 1962) J. Ellroy Enchanters 120: I steered herky-jerky.