I was fortunate at school that nudity was no big deal and staff and boys all showered together in a large communal shower corridor arrangement, where we had to walk through, showering as we went.
We like being at some naturist camp-sites, where there is an unisex open shower area of several showers where men, women, boys and girls can all shower and chat together.
At one Saturday evening swim that we attend from time to time, everyone has to use the ladies' changing room with showers and toilets.
My first memory was in a group shower during a gymnastics camp on a mountain when I was about 8 or 9. The shower room was in a building separate from the beds and was just one tower with a couple heads on it. i remember crunching in to shower before we went to bed. Also throughout middle school most people took showers after pe
My first experience was at secondary school where we were all required to take a shower in a very crowded changing room after PE. I was very self conscious being naked in front of others in those days and always worried about getting an erection. Happily I got more comfortable as time passed. Communal open showers are still common at many gyms and pools in the UK. I have noticed some of the younger guys showering in their underwear and carefully getting dressed under a towel. Others don't shower at all as has been widely noted. I'm glad that I worked through my own inhibitions and I now enjoy the experience of showering with others including mixed sex showers at the nudist swim group.
Most of my life. In Africa British grade schools all communal showers. In South America again after Sports gym or playing on a team again same thing communal showers. In a boarding High school 8 shower heads everyone naked and showering. No one said anything other than perhaps a tease like other people mentioned. Playing on a Varsity team in College again Communal showers. .