Does jerking off in the restroom count? I use to jerk off and cum under my work desk even when I worked with others in the same room. I had my ways of edging it (cock rings, a butt plug, no undewear) and when the moment of truth would approach, I'd just momentarily stick my cock out and shoot my cum load vertically to hit the desk from underneath. The desk had a covered front, so it was relatively safe. And, yes, I got caught once by a female colleague, but I knew she wanted to see me. That's a different story though.