From 1967 (but not officially released until 1987), please enjoy (if that is the word) The Byrds, featuring the song's composer David Crosby on vocals, and "Triad," the musically memorable but lyrically (er) troubling ode to...well, you know to what.
And from 1968, and the (in retrospect, far more uneven than I remembered) Crown of Creation album, here's Jefferson Airplane's better-known version, featuring the irrepressible Grace Slick.
My Jefferson Airplane wanna-be college band used to do a really nice cover of the JA arrangement (those guitar parts were really fun to play live) but to be honest I never really thought much about the song's thematic content back in the day, and until I discovered the Byrds' original in '87 I had pretty much forgotten the whole thing.
Upon encountering it again with the wisdom of years, however, I distinctly recall thinking that it sounded like the kind of song that Dan Aykroyd's SNL character E. Buzz Miller would have really, really dug. Seriously -- you could practically smell the corned-beef sandwich stains on his polyester shirt.
Okay, that's a little unfair to Crosby, and given that the most avant-garde sexual fantasy I've ever had involved two women (in the same year), I may be the wrong person to weigh in on this sort of thing. On the other hand, I do think that, despite my current uneasiness with "Triad," it was always going to be more palatable coming from somebody who looks like this...
...rather than like this.