Even though this post was entered 7 years ago, I wanted to comment based on my experiences.
7 miles from where I live is Black's Beach, a swimsuit optional beach. The first time at Black's I went with a friend in 1978 when we visited from Arizona.. My friend said "What happens if we get a boner?" I replied that we don't need to worry about it if it happens as long as we are not doing anything lewd. It was a warm August day, and there were hundreds of people on the beach, all naked. We were both surprised at how normal it felt to be naked and enjoying the sun and the waves. I don't remember that either of us boned up, but the experience definitely made me want to do it again.
I moved from AZ to San Diego in 1989 and visited Black's numerous times. There is a trail that goes from the cliffs at Torrey Pines Glider Port to the nude beach below. It is a fairly steep climb. The other option is to walk or bike from La Jolla Shores Beach. I decided that I would ride my mountain bike to the gay section at Black's. It is 7 miles each way. There is one small stretch where I had to dismount the bike and carry it over a tidepool. If the tide is not all the way high, it's fairly easy to ride along the water's edge. This was my M.O. for years. It was great exercise, and my reward was the beautiful beach with warm water and lots of other hot guys.
There is some kind of 4' metal ball thing on the beach in the gay section that looks like it was leftover from WW2. I was able to lock my bike to it and could snooze or play in the water without worrying about someone stealing my bike. That ball also allowed me to leave my bike and to walk up and down the beach with just my hat, sunglasses, and a smile. While walking along the water's edge, the motion of walking gave me a semi that slapped back and forth against my thighs. The result was a full on boner. I had never freeballed before, and being used to wearing briefs all the time made walking naked a totally new thing. I didn't feel the least bit embarrassed about the erection and kept walking. Eventually, the boner subsided. I walked past the family beach to the area where the surfers gather (good waves), and then turned around and walked back. Serveral times I boned up while walking. To tell the truth, it felt great to walk along the beach with my dick slapping from thigh to thigh. No one paid any attention to me. I believe that it's a given that men will bone up, and that we shouldn't worry about it or let it stop us from enjoying the beach.
I'm older now, and it's not as easy to get up and down the cliffs. I still make the trek at least once ever summer, and love to be naked at the beach. Despite my age, I still bone up while walking up and down the beach, and enjoy the feeling of my dick swinging without clothes. Meanwhile the beach 3 blocks away is just as nice other than I have to wear a swimsuit. I think that everyone should try a nude beach at least once. Lose your inhibitions and enjoy being in your birthday suit. It will make you hate to wear a swimsuit.