I used to have a hot tub in my house (not anymore dam it) and on a pretty regular basis, I would allow the hot water jets flow over my cock and make me cum. Due to the velocity and high temperature, It would not take long before I would have a nice orgasm. Only down side is that the cum was like hot glue in my pubes.
However, the really hot story I have is a time in Myrtle Beach where being very horny, I was having a hard time keeping my cock from sticking out while in my bathing suit. So my solution to this problem was to go into the water chest deep and pull my cock out and masturbate right there with all the other swimmers around me. Once I had my orgasm, which was pretty intense due to the risk and fun of masturbating so close to the other swimmers, I just put my cock back in my suit and walked back into shore.