I recently had a very erotic encounter with my girlfriend in the pool at my parents house. We were staying over for the weekend. It was hot out as this was July. My parents go to bed early so around 8pm we decided to take our drinks outside and go swimming. It was dusk out and there was still a dim light. My girlfriend and I were having drinks and cooling off/splashing around in the water and I started kissing her on the neck. We made out for a few minutes and then she pulled away and asked if I could go inside and get her another hard cider. It seemed strange for her to ask this just as we were making out but I could use another drink myself and didn’t think much of her request. As I started pulling myself up on the side of the pool to get out, she grabbed me around the waist. She playfully told me she changed her mind and was going to give me a spanking for trying to get frisky with her in the pool. I was facing the edge of the pool with my arms on the deck above and she pulled off my swim trunks. I could see them floating in the water behind me. I was now bare naked with my bottom just above the water line of the pool. She had one arm around the front of my waist to hold me in place and started spanking my bottom with her other hand. I didn’t know what to think as we hadn’t done anything like this before. It was a huge turn on and my erection started throbbing. She spanked me fairly hard going from cheek to cheek. The noise of her hand spanking my bare ass was pretty loud and I was worried it would wake my parents up but I didn’t really care as I was so turned on. After a few minutes my bottom was red and thoroughly spanked and my erection was as hard and intense as I can ever remember. She let me down into the water and i immediately started kissing her neck and chest passionately as I was so turned on. I undid her bikini top and kissed her breasts and nipples, caressing them with my tongue. We made our way to the steps and I sat down on the second step down from the top. She took off her bikini bottom. Now we were both naked. She got on top of me straddling my erect penis. After the erotic spanking and a good 10 minutes of intense erection, it felt amazing to be inside her. She gently rode me while I suckled on her breasts and nipples until she started moaning with pleasure. Knowing she was coming turned me on even more and I let myself go and started coming inside of her. It was such an intense and erotic sexual encounter. Later that night she told me she had been wanting to spank me for a while and since it had gone well I should expect more in the future.