When I was about 13, my uncle had a farm where I went for the summer. It was a poultry farm where he had several hundred chickens in this huge covered house.
Out by the back of this were some ventilation fans that kept the chickens cool. There were two huge fans that drew a lot of air in, and then there was another fan on the other side that drew the air out. They were huge fans, and the fans that drew the air in had small cooling pipes fed by a main pipe.
The outtake fan was terrible; it smelled bad and it always got dust in your hair. But the huge intake fans in the back were nice and cool, even from the outside. It would draw air in, and that created a breeze. The large water pipe was also very cool, and I used to lean on it a lot with my bare back.
One day, it was really hot. I decided to climb on the pipe like some of the workers did, and lean my back on the smaller cooling pipes in the back of the fan. But I wasn't as strong as those men, so I ended up straddling the larger pipe instead of standing on it. It was hard to stay on the pipe because the vibration of the fan made the pipe vibrate a little, and I'd slide down away from the cooling pipes. I found a way to have my foot wedged against a bar on the wall and push my tailbone against another piece to sort of let me relax there and not have to work so hard to stay on the large pipe.
I don't know how long I stayed there, but after a while, I started to feel a little funny. The huge blast of air rushing past me had produced a white noise that kind of left me in a lazy trance. I had kicked off my sandals and had one of my feet at an awkward angle that left my leg vibrating. As time went by, my crotch has settled in some seam on the pipe, and it was lightly vibrating my clit. So my tailbone was vibrating, my leg was vibrating, and my clit was vibrating on a small pipe seam on a pipe that was vibrating.
I started to feel a strange tension in my legs, and I thought I was getting a cramp due to the weird angle my legs were to keep me propped up that way. Then I started to feel like I had to pee a little, but I had just peed an hour ago, so I thought I could hold it.
I am not sure how much longer I felt that way, but it felt good 'holding back the pee,' which is how it felt to my little body at the time. You know how it feels when you have to pee for a long time, and you get to the toilet, and then you go? Like that relaxing of the tension? Well, it felt more and more like that relaxing, and I found if I leaned a certain way, it pushed the seam of the pipe against my 'pee hole' and that felt really good.
My butt started to feel good, and as my thigh vibrated, I became more and more aware of how naked my legs were. I was wearing nothing more than a short sundress and panties. I had barely started my boobs back then and my body was more like a little girl than a young woman. I found I was getting really anxious, and I felt like I just wanted to keep holding back the pee and the longer I held it, the better it felt between my legs. I kind of felt... a little naughty somehow, even though I had no idea what was going on. I felt like the longer I held in the pee, the naughtier I became. I down pressed harder on my pee hole, and even took one of my hands and pressed down like I did when I really had to go.
Suddenly, I felt this growing sensation that made my teeth itch. I suddenly thought, 'Oh no, I held back to pee too long and I am going to have an accident.' But as I tried to get off the pipe, my legs had gotten so sore, it was hard to move them, and I struggled to stay upright and not fall to the ground as I tried to dismount. In the process, I lost my footing, and slid down the pipe a few inches. I tried to stop my slide by gripping the pipe between my legs, and then something happened to me that was unlike anything else.
All at once, my muscles let go and my whole hips and butt started to thrust and pulse into convulsions. I think I let out a shriek because it felt so good, but at the same time, I realized I had peed myself and was about to fall off the pipe. Luckily, the pipe was only about four feet off the ground, and as I fell on my back, all I could feel was the throbbing pulse of my entire hips, thighs, and butt.
I just lay their under the roar of the fans for a little bit, a little scared, and a little out of breath. I found I had only peed a little, and now that I look back on it, that might not have been pee at all. When I got up, I ran back to the worker's bathroom as best I could. My legs were wobbly and I felt really weird. I sat in the hot bathroom, and was surprised I only had to pee a little bit since I felt like I REALLY had to pee during my ordeal. My entire privates were sore, and I felt like I had broken something down there.
I spent the rest of the day in my bed, worrying about having to go to the doctor and explaining what happened. My privates hurt a LOT. But by the time dinner came, I felt a little better. I was sore for days and I never did that again, and until now, didn't tell anyone.
Years later, I found out how to masturbate on my own, and when I came, I realized that must have been my first orgasm back when I was 13.