This happened at work in the 1980's. Me and this girl were working night turn which is midnight to eight A.M.
She wore jeans that night and she brought a kind of short skirt as she was going to church after work. About an hour before quitting time, she changed from her jeans to the skirt. She came downstairs and then a few minutes later, she said she was going to go upstairs and wake the other girl who was working with us. This other girl always takes a nap when working nigh turn. When she headed upstairs, I boldly stooped at the bottom of the steps and watched her walking upstairs. She knew I was watching because after a few steps she turned and smiled at me and then she continued to walk slowly up the steps. Of course the higher she got, the higher up her skirt I can see. I saw all the way up to the elastic of her panties. They were white panties. I was hoping she was pantyless but seeing her panties gave me a boner. I had to relieve myself so I quickly ran upstairs to the men's room and beat my meat. It did not take long for my cum to shoot out of my dick. She knew why I went upstairs.
The first time I worked with her a month earlier, she put her hand on my crotch. She was a hottie. We never did anymore than that because we did not want to get caught and lose my job and we never dated because she had a boyfriend. She was just being a dick teaser.