Skate Park at Night
One evening, when I was in my teens, I rode my bike around 1 in the morning, to a park that was close to my old high school. The park was nice and quiet, and with no people around. I rode to a nearby bridge, and stashed my clothes, and my bike near the bridge, just out of view.
I started to explore the park in the night, completely naked. I reached the far reaches of the park, next to the road. There were a couple of cars out and about, but they didn't notice me.
I made my way over to a sculpture near the back of the park, sat down and stroked myself until I came. It was still dark when I got dressed and left.