Green’s Dictionary of Slang

bazooka n.1

[all f. the anti-tank rocket launcher, first used in WWII; like bazoo n.1 the term may stem f. the Du. bazu(in), a trumpet, in this case f. the shape ]

1. [1910s] a metaphorical part of the body.

2. [1950s] the buttocks; in up the bazooka

3. [1950s] the head, the mind, with implications of stupidity.

4. [1950s+] the penis.

5. [2000s] (US black) an especially large and potent marijuana cigarette, laced with cocaine [note basuco n.].

6. [2000s] (drugs) cocaine, crack cocaine.

7. [1990s+] (US drugs) a cigarette that mixes coca paste and tobacco.

In phrases

up the bazooka (adv.) [i.e. fig. excrement]

[1980s+] (US) a general intensifier, blatantly, excessively, totally, reprehensibly, in large quantities.