The instinct of women to instantly drop whatever good time they may be having if one of their girlfriends is upset. Doesn't necessarily need to be at a prom, but good luck having a prom with out it, as they are training grounds for acts of promraderie in later life such as at weddings and any night at a bar involving 4 or more women.

When some little bitchboy is acting like a little tiny pee pee poo poo baby and messing up the group plans.