The small stretch of skin on a males genitalia between the ball sack and the asshole. It isn't (tisnt) part of the sack and it isn't (tisnt) part of the asshole.
Looking at the condors flying past a double rainbow on the north rim of the Grand Canyon, the chatty group was struck awe-tistic, thus could not speak as the birds with their nine foot wings swooped low over their heads.
The sound you make when you go to sit down but the chair is farther away from your ass than you anticipated, or not even there, so you do a full falling spasm.