Watching A Man In The Park

I live in a small city bordered by a couple of rivers, the small one is on the edge and has a pedestrian bridge leading to a park on the other side which is very overgrown, basically just a lot of trails through thick forest. There usually aren't many people there, especially on weekdays. About five years ago I went there to walk around a little bit and was heading back to cross the bridge again when I saw a man running fast along the bridge to the trail side, I was just a few feet away behind some trees and he didn't look very closely so he apparently didn't see me. He had short brown hair, a blue T shirt and jeans, and a medium build, nothing really distinctive but I got the impression he worked with his muscles, he wasn't a weight-lifter but probably didn't sit in an office all day.

He then ran a short distance down a trail away from me and the bridge, and then stopped suddenly in the nearest clearing. I was curious and walked a little past the bridge in his direction, but down a side trail so he couldn't see me if he went back to the bridge. I saw him standing nearly still facing the river like he was staring at something., and it took me a minute to realize that he had unzipped himself and was masturbating, paying no other attention to his surroundings. He was at least 10 years older than me, but I wasn't at all scared, it was obvious that he wasn't trying to be seen and just needed some urgent relief. I could only barely see his dick as it was covered by his hand and over 50 feet away, but it was obvious what he was doing. I wanted both to keep watching him in secret and also get closer. In fact, I thought about coming close to jerk him off or suck on him--things I had never yet done but occasionally thought about--but didn't dare because I didn't have time to think it through and didn't want him to run away if he knew he had been seen. After a few minutes he finished, I wasn't close enough to see any cum but he vibrated for a bit and then tucked himself away and walked back to the bridge almost as quickly as he came. I then walked over to where he was and after searching for a few minutes saw some drops on the dry ground, and kept looking at them over and over. I even walked away for a few minutes and then came back, I guess confirming that all this was real and I wasn't imagining it, and sort of getting as close as I could to his orgasm without having been there.

Back then I wasn't sure if I was straight or bi, now I now I'm bi, but I still think about this man a lot. I went back to the park many times but never saw him again. I fantasize about see him come back and kneeling in front of him to take in his semen. After that he could either run back across the bridge, or sit and talk to me and I would learn all about him. And then we would plan to meet again there another day. In reality, I don't do one-time stands like that, but this particular incident has burned into my brain and gets me excited. I wouldn't want to do this with any other random guy, it's more like because I saw this one man do it I feel like I own this experience and get to control it. In reality, it probably wouldn't be fun at all, but it's nice to think about.