There is nothing more thrilling than having a quick wank outdoors. Especially when there is a chance I might get caught.
So, in the middle of a wank in my car, I realize that someone is watching me but I'm beyond caring, my orgasm is close so I carry on squeezing my tits and pushing my fingers deep inside my wet pussy until I cum.
Then, when I have finished, I look up and tell my voyeur that he has seen enough and he can now fuck off.