It was not unusual at my gym shower for guys to stick around and get hard during the shower. One time this guy and I were in the shower and when i turned around a 3rd guy walked in and the guy said to me to stay there after he leaves. I got nervous and I just walked out probably still with some soap suds on me. He followed me to the locker area to dry off and he was rock hard but I didn't want to do anything at the gym so I just smiled, threw on clothes quickly and got out of there. There was a trainer there who posed for Playgirl or something and he had guys tailing him everywhere. He was straight but liked the attention he was getting.