Middle school jerking off in class

When I first discovered jerking (6th grade) I could reach orgasm, but I didn't actually produce any cum yet. This meant I could jerk it anywhere I wanted: on the school bus under my jacket, through my pants under my school desk, you get the idea. As you can imagine, I did this with some frequency. In class we sat in little groups of 4 facing each other, so one time while I was going at it the girl across from me noticed how red and focused I was getting during class. She asked, "Are you okay?" just as I finished. I must have mumbled that I was okay. If only she had known.