I'm not much of a swimmer, but I've been in pools enough to know about the return inlet, the underwater opening through which water is pumped back into a pool to keep it circulating. Around eight years ago I was living in an apartment complex that had a pool with several such inlets. Most of them streamed the water back into the pool without a lot of pressure, but two of the inlets, both located at the deep end, pumped water back into the pool at a more forceful rate, especially one in particular. Sometimes I would swim over to the inlet and just enjoy the rush of the water pressure against my body, positioning my back or my stomach so that it would give me a jet-streamed water massage, leaving my skin tingling and extra sensitive.
Well, that stimulating water jet gave me a deliciously erotic idea, and after tossing it around in my head for a while, one day I decided to carry it out.
It was a hot, sunny June afternoon. I slipped on a pair of swim trunks with a zipper in the front and made my way to the pool. Much to my delight, there was no one else there at the time. I entered the pool at the shallow end and quickly made my way over the deep end, where that wonderful inlet was located. I brushed up against the jet-stream to find that it was just as powerful as ever. I looked over my shoulder to make sure no one was nearby, and then I excitedly put my plan into action.
Using one arm, I raised my body slightly out of the pool so that my groin was positioned right in front of the water jet. I held myself in such a position so that from anyone else's view, I would simply be lounging at the side of the pool, taking a momentary break from swimming. With my free hand, I reached under the water's surface, unzipped my shorts, and pulled out my penis, which was totally limp. I had masturbated quite a lot over the previous few days--even earlier that day, if I recall--so I wasn't aroused at all or feeling even slightly horny. If this little experiment proved unfruitful, it wouldn't have been a big deal.
I made sure I was close enough to the water jet to feel the pressure yet far enough away to where it wouldn't be too intense. I held the base of my penis with my index and middle finger while positioning my thumb just behind the head, then turned it upward so that the jet-stream hit me directly at the most sensitive spot, right at the frenulum, where the shaft and the head meet on the underside.
Honestly, I wasn't prepared for what was about to happen. Much to my surprise and delight, my penis instantly responded to the stimulation, and within a few seconds--yes, that's right, SECONDS--I was having one of the most intense orgasms I'd ever had. The sensation was incredible! I had never experienced such a rapid rise to climax before, and that's what made it so overwhelming. It all happened so quickly that my erection and my orgasm were simultaneous. In fact, I don't even think I was fully erect when I started climaxing.
As soon as my orgasm subsided, I quickly put my still-swollen penis back into my swim trunks, zipped up, and moved away from the water jet. It took me a few moments to regain my composure after such an intense orgasm. My penis tingled for a while after the experience, probably because it had never gotten such concentrated and powerful stimulation before.
Needless to say, I couldn't wait to repeat the act--which I did several times--although it was never quite as earth-shattering as that very first time. Not long after that I began dating the man who is now my life partner, so I gave up the water jet for good since I have a regular, fulfilling sex life with him. But I always look back fondly on those water jet orgasms, especially the very first one.