In an unusually candid moment my wife has admitted to masturbating for a co worker. It happened many years ago when she shared an office with another girl and two fellas. One of the fellas was gay but the other fella was into the two girls. He would scrabble around under the desk to look up the girls skirts. I think they must have egged each other on to the point that they would open their legs for him to get a peak up their skirt. Having had his show would then joke about going to the gents relieve himself, except the girls understood he was not really joking. I think my wife (girlfriend then) and her friend were flattered and giving a peak became a regular thing.
My wife told me that the fella had occasionally persuaded the other girl and my wife to pull their panties to one side for a proper flash. She also admitted that outside of work, in the pub, there had been the odd bit of groping and touching. Once in a quiet office moment my wife had been talking about his trips to the gents and he asked her if she'd relieved herself whilst thinking about his peaking. She'd replied no and he'd said that she should, joking he'd want evidence. With just the two of them in the office she said "what about now?" He shut the office door and she put her hands into her panties and rubbed herself with him watching. It was very quick and he left for the gents even quicker.
She told me that she was massively turned on and wet by the dirty talk (I think that it not being with me, her boyfriend, added to the tension).