Room in which high school kids change for gym classes. Usually contain a large open area with benches to change, along with a number of
lockers, urinals and showers.
These are usually very embarassing places to be, as everyone has to
strip down in front of their friends, with no place for privacy. Expect tons of
pantsing and insults about one's body.
Even worse are swim class locker rooms, in which full nudity is much more common, and the showers are more likely to be used. Avoid getting random boners at all costs!