I was in my Cisco class (computer networking) we were taking notes and the lights were out.
We type our notes on the computer, btw. The notes are projected from the teacher's laptop.
No one was in my row that day. I can still see the screen if I am scooched way down. So I scooch and lower my chair to the lowest position. I pull down my zipper and push my underwear down inside my pants. By this time my cock is at its hardest, seven throbbing inches, five inches of girth and veins are starting to stick out. I'm leaking precum, just enough to rub on my head. I pull my cock out of my zipper, enough room to pull it out and point it sort of forward/up and I start stroking slowly.
As I get going, I rub my precum all over my head, making it so much sweeter. Luckily no one notices that I am a little preoccupied. Then notes end and the lights are turned back on. I sit up a little, with my cock out, under the desk. As I sit up my head rubs against the bottom of the table.
We start reading the section, taking turns. I am still stroking, slowly. Then it's my turn to read, and I still stroke my huge hard cock. We finished reading and I was still stroking. That was the end of our work for the day, so we get free time until the end of the hour. Everyone starts surfing the net like usual. I am sitting there, checking my email with my right hand, and stroking with my left hand. As I stroke, I get closer, and closer. I am rubbing that precum all around my head.
Then, it happens. I shoot. I can't get any on my jeans, so I shoot onto the underside of the table, mostly on the carpet. I stroke it a few more times to get all the hot sticky cum out. Then I put it back in my pants, and buckle back up. The hour ends.