I have had sex on the beach several times with complete strangers...right on the shore too, not in the water...It got me really hot to look around and see other guys watching me. There is a nude beach near me and when I was younger, I used to get off by going and teasing the guys...sometimes they got lucky. Of course, now I realize just how stupid and dangerous it was but it was lots of fun. Hubby and I had sex on the each one night too...quite a few people were on the beach that night. Then, of course, there were all the times in parked cars.