So, is there a word for "wedgie" in Spanish? You bet there is. "El calzón chino" is a wedgie. It literally means "chinese underwear". The extreme form of super wedgie is called "el calzón chino atómico".
A "school bully" in Spanish is a "matón de escuela", so in order to say "The school bully gave my brother a wedgie" you could say in Spanish, "El matón de la escuela le dio a mi hermano un calzón chino".
Kids, don't try this at home. I guarantee it will upset your mother.