Douglas Harper's Etymology Dictionary
"vagina," slang, by 1991, perhaps from hoochie-coochie, especially in the blues song "Hoochie Coochie Man" by Willie Dixon (1954), featuring a sexually suggestive phrase that traces at least to the 1893 World's Fair (see hoochy koochy).
Wiktionary
n. (context slang English) cooch; vagina
Usage examples of "coochie".
The Coochie Pembroke Memorial Challenge Trophy might achieve world-wide stature in competition or tarnish un-presented in an attic: with Malcolm it was always a toss-up.
Coochie had left and not actually expecting that things would be different: and I should have known better, as each wife in turn, Coochie included, had done her best to eradicate all signs of her predecessor.
Increasingly amused, I thought of the distant days when Alicia had painstakingly bleached all the old wood, only to have Coochie stain it dark again: and I supposed that perhaps Malcolm enjoyed change around him in many ways, not just in women.