Run

Even at a dead stop, almost no one even gets up yet. Everyone is waiting for you. You know as you stand abd sling your pack over your back, something that barely covers your lower back, leaving the towel to cover everything important. As you make tentative steps toward the sliding bus door, now open and featuring a dozen or so high schoolers waiting for someone on this bus apparently, you feel a tap on your shoulders and spin.

"Sorry George, its my only towel." As the bus lady yanks it off you in one swipe. The moment you realize it, you are completely naked, standing with your cock facing the driver all while mooning the boys and girls behind you.

Wearing just your shoes and your backpack, you pivot, cover your crotch with both hands, and sprint out of the bus towards the massive brick school, you can hear your former busmates chasing after you with cheers and hollering. You pass several students who merely gape in shock at your bare assed display, as well as a faculty or two who merely blanch, "Oh my.", as you pass. You cant focus on them though, your options right now are limited, you could go to class as scheduled, maybe hide in the gym and find spare clothes, or you could just turn yourself into the faculty, maybe they have a plan for this situation