When the skin at a womans arm pit folds to resemble a pussy. Arm pussy, often abreviated to "AP" is the ultimate form of voyuerism. Firstly, women don't hide this part of their body in public, but more importantly AP is a very close representation to a womans actual vagina in terms of lip tightness, and hairyness. AP is a public preview of private nudity.

The space between the side of your arm that connects to the torso -- especially with a weight lifting guy. It forms a unique pouch area.

1. In cheerleading when a male cheerleader goes to catch the falling cheerleader out of the air and accidently misses punching the girl into her pussy upto his forearm.