Green’s Dictionary of Slang

Canadian adj.

(US gay) uncircumcised.

1972		B. Rodgers Queens’ Vernacular.
1979		Maledicta III:2 218: Canadian = uncircumcized, with draw drapes or lace curtain = foreskin (uncut appearing as a feature in sex advertisements).
1986–7		Maledicta IX 53: Canadian n [R] uncircumcised penis; homosexual slang.

In compounds

Canadian bacon (n.) [bacon n.¹ (5)]

(US gay) an uncircumcised penis.

1972		B. Rodgers Queens’ Vernacular.
1986–7		Maledicta IX 53: Canadian bacon n [R] uncircumcised penis; homosexual slang.

Proper name in slang uses

In compounds

Canadian black (n.) [its dark green colouring]

(drugs) marijuana.

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