My biggest fear in school was being naked in the gym showers. I was terrified of getting a boner in front of everyone. It would be the most embarrassing thing ever! I managed to keep things under control until one day after school at cross country track practice. I cut out early because my asthma was acting up and was all alone in the showers when it happened. It actually felt sort of thrilling in a taboo way. I turned off the water and pranced out bouncing and swaying but was suddenly paralyzed by an unexpected classmate. I felt like my life had ended as I stood there dripping, but all he did was smile and give me a nod of approval. Then he turned and opened his locker like everything was cool.
I finally got over my fear.
Yeah I was similarly terrified in the showers but secretly checked out the variety of other guy’s junk in the changing rooms - who was getting girthier, longer, more tanned, all very interesting to a then closeted bi guy. Didn’t think to fantasize about it until I left school, strangely.