Hi Thomas
It isn't fiction. I still really like to push out my piss, mixed with precum out of my cock into my hands and undies. I have only been with a guy once, when I went on a first class hike. I wrote about it in camping.
When I was in high school though, there was this guy in class that I had noticed always seemed horny and would play with his cock underneath his desk. One day one of the girls in our class, who was particularly sexed up, full of confidence and seemed to have some life experience, sat next to him just for the heck of it and started rubbing his cock through his pants and made him come. Judging from the expression on his face and the length of time he held that expression, he must have filled his undies with loads of cum, possibly leaking down his balls and legs. He was so turned on, and so was I, by witnessing this that after the break I sat next to him and kept giving brief glances at his cock and he must have been interested as I eventually spotted a bulge. I took a risk and put my hand there and he spraed his legs slightly, giving me better access. . I carefully and nonchalantly , while looking at the teacher, as if nothing was happening below, undid his zip and reached in for his swollen cock. I could still feel the moistness of the cum in his undies, and the perfume of his cock and cum was just such a turn on. I am sure the immediate class members must have known something was in the air. I stroked his cock slow and tenderly, harder as he was about to cum. I couldn't believe it, he shot loads, all over my hand that was containing it to his underpants and belly and his cock. He zipped himself up and I think he enjoyed the idea of having a undies full of fresh and moist cum bathing his cock and balls. That day, after lunch it was swimming sports for the afternoon, and I was wondering what he was going to do with his jocks. But he just took them off and hung them up on the peg and covered them with his long pants and shirt. I knew and could see the state of those undies and I got a hard on instantly and quickly shot of to get changed in the toilet cubicles so no one would notice. When I came out, everybody was gone. I couldn't resist and went straight over to his clothes and got his undies out and took them with me into the toilet, I breathed in the perfume tasted the three different loads of cum he had deposited that day, and started stroking myself. I was so turned on and so hot, anybody outside the cubicle would have heard my heavy breathing. I started rubbing those cum soaked undies against my cock. Then I just put them on and blew so much cum into them, over and over again, filling up his undies, I used any unstained parts of his undies to clean my self up, put my speedos on and returned his undies where I found them. I realised that at some stage that day, he had pissed in them a well. After the swim meet, I saw him put those undies on and saw him smile and just before he put his long pants on caught a glimpse of his now bulging cock. There was soon going to be more cum added to those cum-ridden undies of his.
I hope you like the story Thomas. I love writing them. By the end of writing them I usually have quite a pool of precum in my undies.
Regards John.