Lifting up a person's skirt, usually with the intent to show off their underwear or bare crotch/butt. Usually this is done either by the wearer of the skirt or someone nearby. It could also be caused by an inanimate object, such as a hook or other object that might catch the skirt and lift it up. It can be done voluntarily or involuntarily (by another person/object).
Use this tag when the skirt is a separate piece of clothing, not as part of a dress. If the skirt is merely being held - not in a particularly revealing fashion - use the tag skirt hold instead.