When you're sweaty, and your sac starts stickin to your inner thighs.

Bat Wings are what guys get when things get sweaty downstairs and your ball sack starts sticking to the side of your thighs.

Unlike bats wing which is performed purposefully, Bat Wings are the spreading and sticking of ones sack to the inner thigh. Usually happens at random, in summer months and is caused by the heat and persperation from the hey-nanner-nanner region.

pulling on the scrotum from the sides so the skin becomes the form of bat wings

When a guys ball sack sticks to his inner thighs, and when he spreads his legs to unstick them, they resemble bat wings..

A woman with large and longer 'flapping' style vaginal skin

Large, very large, monsterous pussy lips.