Also "Hassy," and "The Hassee," it's a term that describes the Perineum, the area located between the penis and anus, or the vagina and anus. The Hassee is given its name from a shortened version of Tallahassee which, given it's location on the Big Bend in Florida, is a perfect example of the location of the Hassee.
If Florida is truly "America's Wang," then Tallahassee is the Hassee.
"It's hot as balls out here...how's your Hassee?"
"Hot and sticky, buddy."
Also can be used more indirectly, commonly as a word that can be said aloud in public without fear of inappropriateness:
Person 1: "I think she was coming on to me."
P2: "She wanted your Hassee."
P1: "Haha, the HASSEE!"