For seven years in the '90s I commuted by train. My stop was the last on the line, and I sat in the forward-most car. Most evenings I was the only person on that car for the last half hour or so. I developed a system for self pleasure that was very satisfying.
I always kept a stash of downloaded stories from my favorite Internet sites, which I printed out, in my briefcase, as well as a supply of paper towels and lube.
Before I left work each day I took my underwear off, so I was free-balling on my way to my normal seat on the train. That was a very pleasant feeling, and got me into the mood for masturbation.
About an hour or so from the end of the line, I would take out a couple of stories and begin reading. It wouldn't take long for me to get hard, and I'd gently stroke through my pants, getting really turned on. Before all the other people left the car, I'd drape my jacket over my lap to provide cover, and I could play with my penis without danger of being seen. By the time the last passenger left the car, I would unzip and bring my penis out. By now I'd be dripping pre-cum, and I'd use it to gently massage the area around my frenulum. Oh, that felt good. The longer I did that, the more aroused I became.
Then as I couldn't stand it any longer, I'd get my lube and run a line down the top of my penis, and grip it very gently. Still reading my story, I'd stroke as slowly and gently as I could with my whole hand, raising my arousal. When I could tell I wasn't going to last long, I'd undo my pants and pull up my shirt enough so I wouldn't mess up my clothes. I'd try to keep up a slow pace as long as I could stand it. As I got close to the point of no return, I'd try to time my own orgasm to the guy in the story I was reading. As soon as he got there, I'd drop the story and concentrate on my orgasm. By this time my penis felt like it was on fire, and I'd suddenly grip it tightly with my thumb and forefinger on the shaft just below the head, with my forefinger right on the frenulum, give it a few quick tugs, and then it would hit. I'd feel one throb, then after a second a second one, then a series of rapid fire throbs where my cum would come shooting out. Normally the first shot would hit about two or three inches above my navel, the second a little lower, and by the fifth it would be just dribbling out.
The ecstasy was incredible as my orgasm relieved the pent up tension of my whole body that had built up over the half hour or 45 minutes that I had been building toward my orgasm. I'd slowly recline the seat, and lay there with my penis gently throbbing every so often in the afterglow, and I'd slowly go soft. My cum would pool on my stomach, so eventually I would wipe up, then hold my penis between my fingers as the feeling drifted away.
By now I usually had just enough time to refasten my pants and dash to the rest room to put my underwear back on, and we'd be pulling into my station.
My wife always remarked about how relaxed I looked when I got home, and said the train must be good for me. She never suspected how good.