Green’s Dictionary of Slang

1. to sodomize [bunghole n.¹ (1)].

c.1940		God Ship Venus in Bold (1979) 103: And every night by candlelight / They bung-holed one another!
1965		Guild Dict. Homosexual Terms 6: bunghole [...] (v.): To pedicate. The association with this meaning can be found in its original meaning, bung (ca. 1589): To close.
1972		C. Bukowski Erections, Ejaculations etc. 55: I want to bunghole you, you got those big cheeks.

2. (US drugs) to inject narcotics [Spears, Slang and Jargon of Drugs and Drink (1986), suggests ‘probably nonce’ but the term plays on the equation of narcotics and excrement, see shit n. (5)].

1959

J.E. Schmidt Narcotics Lingo and Lore.

3. (US) in fig. use of sense 1, to rob, to cheat, to exploit.

2012

L. Berney Whiplash River [ebook] ‘Mr. James robbed UNESCO blind. And every other NGO in Cambodia [...] He bung-holed them senseless’.