Green’s Dictionary of Slang

1. to jostle against, to knock.

c.1786		Grose Classical Dict. of the Vulgar Tongue ms. additions .
1788, 1796		Grose Classical Dict. of the Vulgar Tongue (2nd, 3rd edn).
1975		(con. 1930s) Durocher & Linn Nice Guys Finish Last 90: The next guy that bunts on me [...] I’m going to bounce one off his noggin.
1986		S. King It (1987) 920: He bunted her with one meaty hip and almost knocked her sprawling.

2. (Aus.) to have sexual intercourse, thus n.; bunting, an act of sexual intercourse .

c.1982		B. Tate (ed.) Bastard from the Bush 56: So long as it’s cunt and willing to bunt, / Myself I prefer it to date [Simes:DLSS].
1993		B. Moore Lexicon Cadet Lang. 64/2: ‘Went to the Bin last night, looking for a bunt’ [...] ‘Have you guys bunted her yet?’.
1993		B. Moore Lexicon Cadet Lang. 64/2: ‘I’m going to the boof bag’s for a bit of bunting.’ ‘A good bunting’s hard to come by’.