Green’s Dictionary of Slang

to toady to, to act the sycophant; also as adj., sycophantic.

1930		E. Raymond Jesting Army in DSUE (1984).
1944		J. Cary Horse’s Mouth (1948) 266: Probably a hanger-on [...] Full of parasitic bitterness and bum-suck spite.
1962		Paton & Shah Sponono I i: When I want my freedom, I’ll take it. I won’t go bumsucking ’round any bloody lanie.
1975		A. Bleasdale Scully 45: In school if you bumsuck the teachers they give you another couple of years and stick you in the sixth form. No thanks.