34M, I'm a professor at a state university with large lecture hall style classes. When I first got hired, my sub at the time (not together anymore and not showing photos, don't ask, creeps) thought it would be fun to service me under my desk as I worked on my research and graded papers. It was super hot to ignore them and keep working, but feeling so freaking good. They did their best to distract me, and sometimes it worked resulting in me throwing them on top of my books and desk.

It was awkward when one student came in and my sub didn't stop. My heart was pounding slowly faster and faster but I was trying to keep my cool. This student was upset about their grade and I was very clear that it was simply inadequate for the grade they thought they deserved. They then offered if there was anything they could do to not only get the grade they wanted (a C) but a full on A, and slowly traced their hand down their neck to their bra line.

Hearing this, my sub was pissed, pushed my chair back, and sat up from her knees from under the desk, staring the student dead in the eyes and said, "He's already taken care of" and slowly lowered her head back down onto my cock.

I thought I was gonna get fired, because the student could just go to the department chair and rat us out, but they were so flabbergasted I guess they just went back to their dorm.