Is it true that men are totally naked in the locker room?
Yes.
Men find a locker and removed their clothing. They don't put clothing on again until they're ready to leave the locker room. So, nude to the urinal for a piss. Nude in the sauna. Nude in the shower. Nude while standing at the sink shaving, brushing teeth, combing hair, etc.
Its extremely rude for a man to be clothed while in a men's locker room.
If there are individual shower stalls, then closing the door/curtain means you're jerking off. Best to just leave the door/curtain open. Loretta Skinner
Yes, I was changing when a woman walked in. I don't think it was fair to her or others. There were boys occasionally there so she should not have been cleaning. A few of us talked to gym staff and that practice ended.
Yes it is natural for man to be naked in change rooms and in group showers. At school I try to remain naked as much as possible before sports and swimming classes for this feels very pleasant to me and to be naked with my classmates feels like we are brothers then.