Green’s Dictionary of Slang

(drugs) mescaline.

1969		R.R. Lingeman Drugs from A to Z (1970).
1971		E.E. Landy Underground Dict. (1972).
2001		ONDCP Street Terms 5: Cactus buttons — Mescaline.

1. tequila or mescal [the origin of tequila/mescal in distilling the fermented sap of a maguey (Agave tequilana)].

1975		L. Dills CB Slanguage.
1985		J. Wambaugh Secrets of Harry Bright (1986) 63: That was a lot of cactus juice for the young cop.
2000		Indep. on Sun. 30 Jan. 26: Once disparaged outside Mexico as rot-gut ‘cactus juice’, tequila is now a runaway success.

2. (US) mescaline [play on SE mescal/mescaline, properly the alkaloid 3,4,5-trimethoxyphenethylamine, which is the active ingredient of mescal buttons].

1971

H.S. Thompson Fear and Loathing in Las Vegas 32: And now the fiendish cactus juice took over.

(Aus./N.Z.) in difficulty.

[1924		Bundaberg Mail (Qld) 14 May 2/7: He battles with a fractious horse that lands him in the cactus - then has to meet a girl and smile despite his thorn-perforated anatomy].
1953		Eve. Post (Wellington) 9 Mar. 12: Rather funny you being in the cactus at home – I’m in the dog box with my wife too [DNZE].
1969		B. Mason Awatea (1978) 75: matt: What did they say? brett: That I was taking a risk; that if it fizzled, I’d be in the cactus.
1976		R. Hall Glide Time 54: Why should I get in the cactus just because you make a muck-up?
1984		Wilson South Pacific Street 52: I’m in the cactus. Done a flip. Just lost three thousand smackeroos on the big race.
1988		McGill Dict. of Kiwi Sl. 25/1: cactus phr. in the cactus in difficulties; eg ‘The recent defections have put the club in the cactus.’.
2003		McGill Reed Dict. of N.Z. Sl. [as cit. 1988].

(US) exck. of surprise, amazement.

1933

Williamsburg Jrnl. Trib. (IA) 23 Feb. 2/4: The latest expression [...] is ‘well, seat me on a cactus’.