Green’s Dictionary of Slang

canyon n.

1. the vagina (cf. yodel in the canyon (of love) v.

implied in yodel in the canyon (of love) v. (2)
[US] in P.R. Runkel Law Unto Themselves 258: I finally got my nose warm in ’er canyon.
[US]E. Folb Runnin’ Down Some Lines 152: Who’s gonna flood yo’ hole, fill yo’ canyon up? Me!

2. the anus.

[US](con. 1985–90) P. Bourjois In Search of Respect 38: They take your ass and stuff it with some mad concrete. They fill your canyon. Word!

In phrases

dive in the canyon (v.)

to perform cunnilingus.

‘Euphemisms for Cunnilingus’ at [Internet] Dive in the bushes / Dive a muff / Dive in the canyon.
yodel in the canyon (of love) (v.)

see separate entry.