When I was young I would have the greatest hands free prostate orgasms using the water jets at my Uncle's inground pool. First get rid of the trunks and find the nearest return water jet. Grab the edge of the pool above it and bring your knees up to your chest so that the jet pressure is directly on your taint spot and behind the balls. You want the pressure to hit that spot and roll right up the shaft of your cock. Once you feel your cock growing and your skin tingle just lay your head back and let the good times roll. You will have such a strong orgasm and alot of cum. The pool filter will clean up all of your cum. When you lay your head back and cum it will feel like you are in heaven. Even better if you have a partner to do it with. Midnight swims are awesome.
Very i tense way to cum! Do this at the pool at the gym after swimming laps. Deep end has jets at the perfect level. Just act like I am resting on the side of the pool while the jet is working on my cock. Jet will beat my cock and make it go side to side. Soon it tenses up and have one of the strongest orgasms!