Nude at School
I should have done that when I would go use the restroom during my stretch-breaks when figure modeling. The thing is, however, that I noticed guys would get uncomfortable with me being in the restroom with my bathrobe and flip-flops. If I'd come out nude, they would have had a fit.
Some time ago I had swimming lessons in a school pool. Afterwards we'd all troop into the changing rooms. The other men did an elaborate towel dance. I just shed my trunks and towelled naked before dressing. Usually my female instructor would walk in to use the shower while I was naked (she showered in her swimsuit). I never was that good at swimming, even after the lessons.
I was fortunate to have gone to school in an era when boys and teachers all stripped together in the changing room and all showered together.
I was at school then too. The teachers changed separately. You might think that would stop any inhibitions from the naked schoolboys changing and showering together. But at the end of sports we were all eager to get home.