Barstool Surprise 

A term used to describe a girl who, when sitting at the bar, looks perfectly normal, however, when she gets up out of her barstool to go to the bathroom, you get to see the lower half of her and are surprised that it's quite a bit larger than someone with that small of an upper torso should have.

Damn, that chick has some serious barstool surprise going on down there!

Barstool Surprise by Korban July 1, 2009