I did experience the YMCA nudity that has been mentioned in prior posts. Sometimes, when I was in elementary school and junior high school, females would be present at swimming lessons... moms, sisters, and female (high school) swimming instructors/lifeguards (obviously, the high school girls wore swimsuits).
More recently, my GF took me to a private beach on a small lake where CFnm was the plan. I am usually dominant in our relationship, but on that particular weekend we had switched roles, and I was obligated to be submissive and obey pretty much any instructions she gave me.
I did NOT know ahead of time that this private beach outing was going to be a CFnm experience. And neither did my GF's friends' husbands/boyfriends.
After we had all been having a good time (seven couples) for about 2 hours, my GF said, "You're my BOTTOM for the weekend and I want you to give me your swimming trunks for the rest of the afternoon." At first, I didn't realize (none of the men did) that we were all being given the same instructions simultaneously. So each of us was thinking that he was gonna be the only naked person at the beach. The women had orchestrated this perfectly, because none of us were facing another couple to see, or close enough to another couple to hear, that we were all in the same predicament.
I actually did start to protest, but my GF firmly reminded me that she was in charge that weekend, that I was required to obey... and that, if I didn't hand her my swimming trunks immediately, I would be punished severely for being disrespectful and disobedient.
I knew that her instructions were well within her authority that weekend, and I was beginning to feel the impending embarrassment. I knew that I had to strip out of my trunks, while facing my GF. And, I assumed that, when I turned around, six other couples (all wearing swimsuits) would be seeing me completely naked. I had an erection within about 15 seconds!
It was humbling removing my trunks while facing my GF, but the thought of turning around was actually really scary. But, of course, my GF said, ”Well, you can't stand there facing me the rest of the afternoon. And it looks like you need to take a dip in the cold water... go junp in the lake, and don't come back with that erection."
When I turned around, I saw the six other men also turning around. All seven of us has penises standing at attention. We each later admitted that we looked (trying to not make it obvious) to see that we weren't the only guy with a hard-on.
The ladies had quite an afternoon planned, and the next several hours were a combination of incredible CFnm humility, arousal, and discipline!