I worked at a copy shop back when I started college. I worked mainly nights and alone. We rarely had walk-in customers and did mostly corporate jobs (manuals, financial reports, etc.), but repair techs and paper delivery guys were always there fairly late as I worked alone. After 9pm, we officially closed to the public and I'd just turn off all the lights and run the machines in peace.
One of the repair guy was in his 50s and always seemed to be throwing out vibes he was flirting with me. One night he after we closed, he was finishing up replacing a fuser and was asking me about my girlfriend and that last time I got laid. I laughed that the last time I got laid it was definitely not with a woman. One thing led to another and I was bent over my little work desk with my pants around my ankles taking his cock with the help of some of my boss' Bath and Bodyworks vanilla hand lotion.
He had just pumped a load into me when we heard the back door opening. I don't think I ever pulled up my undies and khakis so fast. My boss had forgotten something in her office. The repair tech skedaddled and I was standing at one copier pretending I was checking our the job that was running. She came up to see how the night was going and casually goes, "Oh no...it looks like that you accidentally sat in a spill."
I tried to feign stupidity, but even with the ambient light I am sure she could see me turn bright red. I excused myself to the bathroom to look at my butt in the mirror to see a decently large wet spot on my khakis. I'm guess the lotion and cum I didn't have time to wipe up were to blame.
I assume she knew, but she never expressly said anything further. But the same tech stopped by frequently on his way home after that night. I had more sex in that store I think than I have ever had in my own bed lol