Green’s Dictionary of Slang

boob n.1

also booby
[booby-hatch n. (1); note WWI milit. use for detention cells]
[20C+]

1. (orig. Aus.) orig. milit. use, a prison; thus (all Aus./N.Z.) boob dot, a small blue dot tattooed beneath the eye, indicating a spell in borstal or prison; boob gear, prison uniform; boob talk, prison jargon; boob tat, a prison tattoo; boob tea, weak, prison-brewed tea; boob weed, prison-issue tobacco; also a vb. see cite 1908.

2. (US) a police station, esp. the police cells, a local or city prison.

In compounds

boob blue (n.) [blue n.1 (2b)]

[1980s] (N.Z. prison) alcohol made from brasso metal polisher.

boob cat (n.) [cat n.1 (5)]

[1980s+] (Aus. prison) a prisoner who suspends his usual heterosexuality for a homosexual life while in jail.

boob happy (adj.) [-happy sfx (1)]

[1980s+] (Aus. prison) institutionalized; no longer able to survive outside the prison environment.

boobhead (n.) [-head sfx (3)]

[1960s+] (Aus.) a prisoner, esp. an influential one.

boob rat (n.) [rat n.1 (1h)]

[1950s] (Aus. Und.) a prisoner, esp. a recidivist.

In phrases

do boob (v.)

[20C+] (Aus. prison) to serve time in prison.