When I used to drive home more often back and fourth I would get horny on the long drive back and so I started a habit of jerking off in my car during the drive, good stuff. I came a few times while driving but a few times, if I could hold it in, after half hour or so of jerking, I would pull into a rest stop or quiet parking lot and finish myself off so I could clean up and not have jizz flying around my car while weaving in and out of traffic.
I found the build up to be incredibly hot and I would have very intense orgasims so I made it a common practice, did it regularly on the drive to and from on long trips (which was almost every weekend) and kept some lube, a cock ring, and lots of klenex in my glove ox
Well on one occasion, it was 7 or 8 in the afternoon, still light out and after a good half hour or so of jerking with one hand and driving with the other, i decided to pull over to a nearby wooded rest stop area. The place was a regular for me and I had come here many times, there was one old looking jeep parked there and there wasn't anyone in it so I parked next to it for cover in case another car pulled up. So there I was in my car, my pants were already off and I dropped my boxerbriefs to the floor. Lubed up my palms some more with the KY that was sitting on the passenger seat already and went to town on mr. happy.
Now since I had already been pumping myself for a good while now, it took just a few strokes before I felt the familar pleasure of my hot cum pushing out of my cock. I closed my eyes, let out a low moan as I pumped up an enormous amount of jizz all over my chest and car, I even shot a bit on the cieling of my car.
The next thing I realized was that the car next to me was not empty! I looked up to see a woman, probably in her early 40's looking down at me in plain view. She must have been reclined and sleeping but she certainly had seen what just happened, I drive a lower car so she certainly saw EVERYTHING! So there I was, naked except for my underwear around my ankles with cum all over myself and my car, lube in the passenger seat, and I was still milking my semi hard cock (with cock ring) in one hand as the last bits of jizz oozed out my dick. She didn't look offended however, just gave me a blank look and surprisingly it turned me on more than anything!
I actually smiled back, and even, get this, wagged my dick at her before I drove off. I was so hot that as soon as I got back on the freeway I resumed jerking off, and later came in my car for a second time!