These are all true experiences. The first one is about masturbating in the parking lot of a convenience store in full view (kind of).
I've been into masturbating in public places for several years. I never do it for someone to see, but the thrill is that someone might, because I masturbate in really public places. I worked at a university and during the day, I'd have to run errands. I took the opportunity to drop by the on-campus convenience store for a drink and a wank. The parking lot was open to two cross streets, on a corner lot, and on one side of the parking lot was a rock wall about waist high, just enough to hide what I was doing. I went into the store, headed straight for the men's room and peed, and then, after shaking my dick off, I pulled my balls out of my pants, along with my dick, then arranged my shirt to barely cover my junk and then I bought my snacks in the store, aware the whole time that my cock was growing hard and pushing against the light fabric of the shirt, just on the other side of the counter from the clerk and near anyone who might be walking behind me.
When no one was standing close by in the store or coming into it, I raised my arms a little to let the cock show as the shirt settled around it. By this time I was rock hard and even feeling a little precum slick the tip. Now for the fun part. I went back outside with my drink and stood by the rock wall and set my drink on the top of it, with my back to the parking lot, facing the street. In the meantime cars were coming and going in the parking lot and people were going in and out of the store, most of them taking little notice of me at the rock wall, with my cock hanging out, just barely hidden by my position at the wall. And with one hand, I began a slow stroke, feeling how hot my cock had become, swollen from the excitement. In the moment when I felt myself about to come, I threw caution to the wind and just whacked off, not caring if someone actually noticed. I came on the wall, and then just casually covered my still throbbing cock with my shirt. I was still trembling from coming, my knees feeling weak, and the thrill of what I had just done gave me great pleasure. And I stepped aside to allow my cum to show as it ran down the wall, as I sipped my drink and watched all the people come and go.
I did this about three times at the convenience store, each time getting a little bolder, facing away from the wall with my cock sticking out, hard and throbbing, and if someone saw me standing there I casually hid my cock with my drink. The stains on the rock are still there, if you know what you're looking at.