Before I met my wife Diane she used to work in an office in the city. The office was next to a block of flats. Diane and her female co-workers had noticed that when they went to the locker room during the winter a young man could be seen going about nude in his flat. He was obviously aware he could be seen by the women in the locker room.
Diane decided to give him something to look at. One late afternoon, when it was already dark, she went to the locker room and saw the man was in his flat and was nude. She made sure he saw her by walking in front of the window several times. The man settled down in an armchair and although Diane could only see his top half, she knew, by the movement of his right shoulder, that he was masturbating whilst watching her.
She removed her sweater and stepped back to lean against a locker. She unbuttoned her blouse and slipped a hand in to stroke her breasts while her other hand went down inside her pants. She then started masturbating, all the time watching the young man watching her and himself masturbating. It didn't take too long for her to reach a powerful orgasm which was obvious to the young man.
Diane stood fingering her clit for a few minutes more and then got fully dressed and left the locker room. She never did this again in the locker room but told me about it years later which excited me tremendously. More to follow.