I have done it when out in the desert, but the most exciting time was when I was with a buddy of mine when we used to work in Las Vegas. Hot summer night, we would drive around, him clothed in his truck, me totally naked in the passenger seat. Anybody looking at us would think I had shorts on, just my shirt off. My friend would reach over and stroke me and keep me on the boil.
We would head towards Lake Mead and before we went thru the pass, he would turn off the road and park the truck so it was overlooking the whole valley. We would get into the back of his truck with a shell on it, and go down on each other while watching the lights below. Other times we would go out to the lake during the day, find as private a spot as we could, get naked and go skinny dipping with some nice touching and stroking. This was in the early '80's, so the lake was really full back then !
We would then walk back to the truck and he would lean down and suck me off and I him, then drive back into town. Being in the military, this was way before don't ask, don't tell, so it was exciting but always a bit nervous about getting caught of course !