Ned's Declassified School Survival Guide - Twins?
On the episode "Dismissal" Moze and the rest of the girls have to go to the bathroom, but has to wait for a long line. To fix this problem Moze dresses as a guy to go to the boy's bathroom. This is where the slip up happens. Moze walks by a kid (the one who she punches in the arm). The same kid is in the bathroom wearing a different shirt when everyone notices Moze is a girl.