Agree that an erect penis is a sign of masculinity and sex and love, as a man all are good. But maybe there is a way to display or not. At the beach, enjoying the sun all over, hey the happen. But maybe going for a walk on the beach sporting one is a different matter. Time & place? Walking along the beach with a hard-on does seem to me to be an attention seeking thing. I'm not saying be ashamed, not at all and far from it, but maybe be mindful of others.
I have walked into the ocean with one to have a swim but also preferring it is relax, I was not after attention. IMHO walking along the beach with one is not the best idea. I've seen one guy in particular at one of my local CO beaches and he purposely fluffs and gives himself a hard-on to walk the beach so people will look. Textiles walk that beach all the time, I just ask why.