Cat's out of the Bag

When a woman doesn't wear any underwear, especially if her pussy is somehow exposed while not wearing underwear. You cannot call it going Commando like when a man doesn't wear underwear. It's called that because your dick is somewhat exposed to the elements.

"Dude, when the wind just blew a minute ago this hotties dress went up high and she wasn't wearing any underwear...Cat's out of the Bag!!"