Green’s Dictionary of Slang

(orig. US) to toady; hence as n. ass-kiss, sycophancy.

1952		J. Jones From Here to Eternity (1998) 340: He had earned the management of his gambling shed by being in the same company 17 years and ass-kissing his superiors every minute of that time.
1961		(con. early 1950s) J. Peacock Valhalla 268: That rank-happy bastard could ass-kiss all he wanted to.
1962		S. Longstreet Flesh Peddlers (1964) 327: Never petty, never ass-kissing or polishing the red apple for anyone.
1977		Sun. Mirror 21 Aug. 8: We weren’t ass-kissing.
2003		Simon & Burns ‘Stray Rounds’ Wire ser. 2 ep. 9 [TV script] This new Asec, thinks it’s all loyalty and ass-kiss.
2017		Young M.A. ‘Walk’ 🎵 Dick riding, ass kissing / That’s somethin’ I know nothing ’bout.