Jacked off in class

Well I know it’s not normal but I jacked off in science class once. I’m from the uk and when I was in my final year at high school a girl I kinda liked was sat infront of me in science and this day she wasn’t wearing a typical English uniform skirt she was wearing a tight one. In science we sit on stools because they’re easy to put away during practice and when she sat down she was like leaning forward resting her head on her hands and kinda sticking her butt out, I could really see the shape of her bum and it really turned me! So I then pulled my school jumper over my crotch and slowly jacked off until I cummed in my pants, no one even noticed not even the person sat next to me who was at shoulder touching distance!