Bikini Drip
The sweat that gets in-between your butt cheeks and causes your underwear/bikini to become moist.
"Dude, it's so hot today. I'm totally getting a bikini drip."
Person 1: "Did you pee your pants?"
Person 2: "No, it's just real hot today. I'm getting a bikini drip."
Person 1: "Did you pee your pants?"
Person 2: "No, it's just real hot today. I'm getting a bikini drip."