My first "social nude" experience was not really a nudist situation. My wife and another couple had taken an evening trip to Strawberry Park hot springs near Steamboat, CO. We didn't take suits with us because it was warmer to deal with the heat transfer of water on skin than water on wet cloth (much colder).|
It took several years before my next trip to Strawberry Park, this time, we were camping near the hot springs and I went to take a morning soak. The couple in the springs was undressed so I asked permission to join them, stripped my suit off and climbed in.
Fast forward a couple of years to many trips to San Diego for work. I visited Blacks Beach and San Onfre a few times. Work also took me to Germany where I was able to Sauna as much as possible. Here, I also dresssed (or undressed as such) like those around me did.
From the time of my second hot springs trip to the first beach trip, I spent quite a lot of time trying to figure out how social nudity fit (or didn't fit) with my faith.