This happened a few years ago when I (M25) single.
After a long hard day at work on site, there was nothing I enjoyed more than pulling my cock out and massaging it, edging myself while driving home in my van, usually a good 45 minute drive. I enjoyed the higher viewing point my van gave me, looking down into cars I passed. Particularly those driven by pretty, young girls. I have a thing for petite slim girls, with slim toned arms, dainty wrists and delicate hands, imagining their fingers wrapped around my cock. The angle from such cars to my van means my cock goes unseen by those just feet from me. Well, that is the case until a large SUV pulls up alongside…
I was stopped at some lights, slowly stroking my cock, running my thumb through the pre-cum leaking out, when out the corner of my eye I caught an black Range Rover Sport pull up on my nearside. Instinctively I tried to cover up my hard cock and causally glance to my left to check the driver out. It was a petite Oriental girl, maybe late 20’s, shoulder length dark hair and smooth pale skin. And judging by the look on her face, she had seen what I had been doing. Instant embarrassment, although my cock throbbed a little. Luckily at that moment the lights turned green, and I quickly pulled off.