Swamp Balls is the action of having a constipated face on because, you don't wear underwear on a hot sweaty day, and your ball-sac gets stuck to your thighs, in which you then have to put your hands down your pants and fix them nuttsssss.
Karen: Ayo Danny what's wrong, you look mad constipated.
Danny: Nahhh man, I just got Swamp Balls.
Karen: Ahhh Shit, I hate those.
A horrible disgusting odor that comes from the stench of having not washed the male genetalia for many days and the male testicles brew in the odiferous ball sweat thus creating the ball swamp