I have a pretty hardcore foot fetish, and a couple of years ago a female co-worker of mine wore these incredible sexy foot exposing shoes. She kept flipping them on and off at her desk and kind of dangling them. I think she knew what she was doing, or at least I like to think she did (maybe that plays into the fantasy I have), but I remember getting rock hard and excusing myself from the room very suddenly. I don't know if she read it on my face, but it must have been a bit obvious what was going on, especially since I had to turn my body at odd angles as I left so she couldn't see the bulge. I ran immediately to the bathroom and furiously stroked one out. I was literally shaking I was so excited. They kind of looked a bit like these. Needless to say I have a pretty decent collection of foot fetish pics on my computer, which my girlfriend and I both enjoy. I'm pretty lucky that way.
My face is always flushed when I'm aroused therefore I have pretend I'm really embarrassed ... I go like this when I go to porn shops to purchase toys or when I go to Adult Theaters
I had a few times years back in the bathroom stall at work, but then some numbskull replaced the toilets with the "sensing" kind which in itself isn't so bad, except if you lean back at all, you basically hit the button and it flushes. After accidently flushing the toilet about 5 times I gave up and grumbled back to my desk
I've never done it while at work, but I did back in high school during class. I had to make up an exam that I had missed so i had to do it during class time. When my teacher went to hand me the test she dropped it and bent over to pick it up, I saw straight down her shirt (and I had fantasized about her before). This got me in the mood. She put me in the back room so that it would be a little more quiet. Unable to focus on the test because of her I started to rub from the top of my pants, that wasn't enough so I eventually just whipped it out and started going to town. She walked in to check on me once, but I was able to hide my dick with my sweatshirt. As soon as she left I spewed everywhere. The adrenaline of almost getting caught made the orgasm amazing!