My university has its own gym, where only students are allowed to train and the trainers themselves are still studying (mostly medicine or sports science etc.). There is a trainer there who is always very nice to me. She always smiles at me when I greet her or say goodbye, otherwise we sometimes chat during training breaks. At first I didn't think anything of it because she generally seems like a friendly person who is just nice to everyone and who everyone somehow likes. She is about 1.65 m tall, has light brown hair, usually with bangs and tied back in a ponytail. She is not "thicc" in the colloquial sense, but is very fit with a very well-shaped butt and thin stomach. The gym usually closes around 11 pm, I usually train so that I'm finished right then. One evening she was there as a trainer and I was the last one left in the gym. She said to me "Don't take too long getting changed so that we can all get home on time." That was no problem for me and I started to change. As I had just taken off my T-shirt, there was a knock on the door to the changing room and she asked "Can I come in for a minute?" "Sure," I answered and the door opened. I was sitting on a bench and she came in. She had already taken off her tracksuit jacket outside, so she was standing in the room wearing only black tight leggings and a sports bra. "I think we can do something a little longer together today," and grinned at me. I immediately got horny and before I knew it, she was sitting on my lap. We kissed for a short while and I started to knead her bottom. At some point my hand moved between her legs, where she was already quite wet. I thought that it would be a bit uncomfortable here on the bench and thought about where it might be a bit more comfortable. In the gym there is a sofa and an armchair where you can rest during training and where the trainers always sit. So I stood up with her and carried her to the chair, as that was where the space was the largest. She knelt on the seat and took off my pants and boxer shorts and started giving me a BJ. I let her do it at first, but at some point I took her head and pushed it in further. At some point she said that I should show her what I could do, so she turned around and squatted in front of me in doggy position. She was still really wet so I could just put it in her pussy. Since I didn't know what she liked, I started slowly and gradually got faster. The faster I went, the more she moaned and the creamier her pussy became. At some point I really went as hard as I could, her legs were already shaking slightly and her ass was already all kinds of red from the claps. At some point I wanted to make her squirt, so I stopped for a moment, turned her onto her back with her legs on my shoulders and carried on. She held my hand, moaned loudly and her eyes rolled back in her head. She got wetter and wetter. At some point she screamed briefly and it was already dripping out of her. I pulled my cock out for a moment and she actually squirted all over me and the nice leather chair. But I wasn't finished yet, so I put it in again until I came too. After I shot a big load in her pussy, we both grinned at each other. We were both exhausted and her legs were still shaking. She said sarcastically, "Great, who's going to clean all this up now?" We rested for a bit before we went to shower together and then cleaned up. She came with me afterwards, but we agreed that that was enough for today. To this day she is a good friend of mine and I often meet up with her for fun.