Green’s Dictionary of Slang

ass-kisser n.

also arse-kisser, butt-kisser
[ass n. (2)/arse n. (1) + SE kisser]

(orig. US) a sycophant, a toady, one who curries favour.

J. Adams Diary & Autobiog. (1961) 300: [...] have made him in Thatchers Phrase a shoe licker and an A—se kisser of Elisha Hutchinson .
[US](con. 1944) L. Giovannitti Prisoners of Combine D 162: ‘Ass-kisser,’ Storch muttered.
[US]A. Lurie Nowhere City 26: Ass-kissers and creeps, to you; sucking up to you.
[US]F. Elli Riot (1967) 25: He must look like a fourteen-carat arse-kisser.
[US]E. Thompson Garden of Sand (1981) 66: We don’t need to cater to such a lot of ass kissers, ignorant goody-goodies, and chumps. Good riddance!
[US]R. Campbell Alice in La-La Land (1999) 128: Some junior ass-kisser came up with the idea of the network financing a three-feature production deal.
[US]Eble Campus Sl. Apr. 2: butt kisser – someone who flatters a professor or superior for personal benefits.
[US]T. Fontana ‘To Your Health’ Oz ser. 1 ep. 6 [TV script] You can never accuse you of being an ass-kisser.
[UK]Observer Rev. 18 July 9: An industry full of ass-kissers and charlatans.
[US]J. Lerner You Got Nothing Coming 118: I strive for a courteous and helpful tone, a legacy of my years as a corporate cubicle slave and not infrequent ass-kisser extraordinaire.
[UK]C. Miller Salt and Honey 41: Come on, arse-kisser, now’s your chance.