Green’s Dictionary of Slang

1. departure, escape [bunk n.¹ ].

1992		R. Puxley Cockney Rabbit.
2001		D. Looser Boobslang [U. Canterbury D.Phil. thesis] 140/2: pineapple chunk n. a cell bunk.

2. semen [spunk n. (3)].

1997

Roger’s Profanisaurus in Viz 87 Dec. n.p.: pineapple rhym. slang. Sperm; semen. From pineapple chunk – spunk.