Long ago, my girlfriend at the time stopped by my office at the end of her day, close to the end of the workday at my work. She hung out for a bit while I finished up my work, and when we noticed that there was nobody else around, she said she was horny and looking forward to going home with me for some fun.
That talk got me aroused, so I showed her my growing bulge. We ducked into a nearby conference room, after ensuring the office area was truly empty, closed and locked the door, and clothes started coming off.
While it was a sexy thing to do, conference tables are not comfortable, so there was no repeat of that scenario.
Another time, with another woman, who joined me at a place where I volunteer. I had a one hour break between activities, so I snuck her off to an isolated back room. I unzipped my pants and she gave me amazing head, then we found a comfortable spot where I then proceeded to fuck her. We both returned to the public area with big smiles on our faces.