The genitals of a drunken woman. Derived from the term "hooch", a slang word for alcohol and "coochie", a slang word for a woman's genitals. The meaning becomes clear when you know the root-words involved.
Frank: "Where's Dave? I thought he was partying with us tonight!"
Jim: "He'll be back in a minute, he's doing the hoochie-coochie."
Frank: "Dave's girlfriend is such a lush."
A game for two (or more) people in which one person reveals his or her erotic wishes, and the other person fulfils them. Next time round the roles are reversed.
Fancy coming back to my place to play hoochie-coochie?