As a science major in school, I had occasions to perform 'field work' in remote parts of the world, both in the US and abroad. As these locations are sparsely populated, it's easier for a shy guy like myself to entertain exhibitionist tendencies if I'm almost positive I won't get caught in the act.
One such occasion took place in a desert region of the western US. I was working alone all summer, and it got pretty darn hot during the day. As the day progressed, I shed more and more of my clothing. Eventually I found myself at a ridge line in the middle of a remote mountain range, where I stopped to take a break. I poured some water over my chest to cool down, but that only made me hotter. It wasn't long before I was sitting on a hot rock with my shorts around my ankles, jacking away. The feel of the hot, dry midday sun on my reddening body increased the intensity of my fist pumping. Using my own sweat as a lubricant, I lay back on the rock and imagined an audience of local women around me as I shot several thick ropes of cum onto my chest and stomach.
After that day, I arranged to have several more 'naked days' in the desert. I would take the whole day off and drive to some of the regions remote sand dunes, sometimes with a cooler of beverages and a good book. Once there, I would sit naked in the desert, reading, getting mellow. I would always play with my cock in the sun at various points throughout the day, but stop short of actually cumming. Then I would end the day with a jerk at sunset and a massive cumshot.
The closest I got to getting caught was when I set up my naked day closer to the railroad tracks than I thought! When the train came past, I was in mid-stroke. I'm not sure if the engineer saw me.
On another occasion, I was reminded of how many air force bases there are in the western US when several jets flew low right above me, as I lay fully exposed to the heavens.
I hope to get back to the western US in the future, to get another great 'no-tan-lines' tan and reconnect with the heat of the desert.