I used to work in a retail shop with a small staff. One of the girls there had a filthy mouth and a reputation, which made her and i get along just fine. The chemistry between us grew slowly, but we were both seeing other people so the tension just built and built without any release.
Since it was a small shop run by people all in their 20s (at the time) there were lots of jokes about us fucking in the back room, in one case where she and i got in position and very briefly dry humped as a joke for the other staff, but also that only made us more turned on for each other. During this period i found myself without a car, so she offered to drive me back and forth a few times while the situation got sorted out, and let me tell you the stars fucking aligned.

One night it was just her and i working and you could cut the air with a knife. The entire time we were making innuendos, dirty jokes, finding excuses to touch each other. More than once she purposefully stuck out her tight little ass where i needed to get by, and i squeezed past, grinding against her while she pushed back at my very obvious jean boner. After hours of edging each other we closed, and she said "you know, if you want to drive, i could do something else." And if there's one thing life taught me it's not to say no to stuff like this so i didn't question it. We locked up, she gave me her keys, we got in the car, and as soon as I revved that engine her hand was on my cock.
We started driving and she kept rubbing through my jeans, but stopped briefly to unfasten hers and shove one hand down her panties. I was rock hard. She moved back to me and started getting my zipper undone, and we pulled to a light and helped get my pants down enough for my raging boner to flop out. She laughed a little, and told me she was surprised, but didn't know why she would be, and then just got right to licking my shaft. By this point we were almost home, but i didn't want to stop. I pulled around the far side of my apartment while she started kissing the tip, and parked. I grabbed her head and she immediately started bobbing. It felt so fucking good and she kept taking these long, deliberate deep throated gulps between faster ones, stroking. I kept trying to grope and play, but couldn't find a good angle, and was getting close. I told her i was going to cum. She just stopped for a second to say "it's ok cum in my mouth" and kept at it. Between how fucking hot the situation was, her amazing fellatio skills, and the fear of getting caught i blew a giant load into her mouth. She swallowed the whole thing. I wanted to return the favor, finger her or anything, but before i got a chance to ask she told me she had to go. Then after that we never spoke about it and went back to working together like the whole ordeal never happened.