You are lucky, for now... oh no, I called it

You run to the East wing, where you have lessons. Happily, you weren't really late, Professor wasn't there yet, only few of the best students (counting you) were here. You sit while panting loudly. Run this long has exhausted you physically. Every single one of your limbs were too worn out to lift them up for good two, maybe three minutes. Yeah, every single one except one. You realize in horror that your shaft is still standing on attention, aching for more pleasure. You remember how incredible it was under your shower. But you couldn't jerk of now! Lecture will start in few minutes and counting how long you were it took before, you were sure you have no time. From the other side, your libido has increased very quickly, as you noticed that this fast. You started calculating the odds. If you DO jerk off in a bathroom, you can be late but with sharp mind once more. If you DON'T rub one out, well... in a couple of minutes sex and your gushing with precum member will be the only thing you will be able to think about. You don't realize, as you start fantasizing about rubbing your big, smelly cock, about smelling the lewd odor of your own sweat and cum, maybe even autofelatio... You notice when you feel your mouth started to drool more and more with every second. You shut your lips and froze for a moment. What should you do...?