Another slang term for the area between a woman's legs. It's slightly less offensive than snizz or twat and certainly better than that word, but it's by no means polite; you wouldn't want your mother to hear you use it in that context. The word is unusual in that it's only used to refer to genitalia with ample pubic hair; in fact, it sometimes refers to the pubic hair alone. (Both of these meanings make sense, given that a beaver is a fuzzy critter.) The term has become less frequent as the removal of pubic hair has become more and more common, but it does appear in several phrases:

Beaver cleaver. The penis (the etymology is obvious).

Split beaver, wide-open beaver. Deprecated terms for the "spread shot" in pornographic magazines, in which a woman is spreading her legs to reveal the inner labia, clitoris and vaginal opening. Kurt Vonnegut uses these phrases in at least one of his novels.

It was also used as a joke in the movie Naked Gun. Jane is looking for something on top of a bookcase. She climbs up on a tall ladder. Frank Drebin (played by Leslie Nielsen), is watching from below and has a perfect view up her skirt.

"Nice beaver!" he says approvingly...

...at which point, of course, she hands him a rodent-like mammal on a stand.

"Thanks," she says coyly. "I just had it stuffed."