Green’s Dictionary of Slang

1. (orig. milit./prison) any form of stodgy food.

1950		P. Tempest Lag’s Lex. 60: depth-charge. Prison ‘duff’ [...] Anything heavy or stodgy, such as dumplings.
1985		R.G. Barrett You Wouldn’t Be Dead for Quids (1989) 92: He was standing outside the Flying Pieman [...] getting into a nice fresh ‘depth charge’.

2. (US) an ejaculation.

1966

Trimble 5000 Adult Sex Words and Phrases 61: depth charge (Vulg.) The discharge of Semen planted by the male during Coitus.

3. (N.Z. prison) contraband smuggled out of prison in the anus or vagina.

2001

D. Looser Boobslang [U. Canterbury D.Phil. thesis] 55/1: depth charge n. a small package of contraband inserted into the vaginal or anal orifice, so as to be safely smuggled into or out of prison.

4. (US) very strong whiskey.

2023

(con. 1962) J. Ellroy Enchanters 285: I sipped bourbon. It was depth-charge stuff. It ran at least 140 proof.