I went to WNBR once. It was awesome. I was not the biggest penis around, I'm a grower. Hundreds of naked people biking through a major city, it was great. I felt like the surprise of it as we biked through the city really made a lot of people happy. The funniest part was when we biked past a church and there was a wedding party outside all dressed up.
I also went to a gay nudist campground once. There I did kind of feel like the center of attention because my boyfriend and I were probably the youngest guys there (we were about 30 at the time).
I've been to NY Jacks once too. Probably around 50-60 guys in 2 rooms stroking it. In that scenario I had an erection, so yes I was one of the biggest guys there, and a lot of people wanted to touch it. I found it all a bit overwhelming though. Being around so many hard naked guys was a turn-on, but most of the guys themselves were not.
I also auditioned to be a nude model at an art school. They brought six of us into the room at a time, three of us at a time got naked and stood on platforms and posed for the 4 "judges" while the other 3 models sat and watched. I didn't get the job.