Arousal becomes an issue

I am directed to my next class and am **** to walk through the halls, hands locked at my sides, as girls surround me, staring at my still rock hard member. I keep my head down, cheeks flushed with humiliation. My cock seems to throb from all of the attention.

When I finally make it to class I get a small reprieve from the stares, as the desk provides a small amount of cover, but my erection doesn't subside. I am having trouble paying attention to the lecture, just running through the experiences of the day in my head over and over again. Having to undress in front of Sarah and Jessica, changing into the jock strap, learning all the new rules in the assembly, Natasha flashing me, and finally my grand humiliation, then back to the start. My cock is pulsing and pre-cum is leaking out. I remember that 3rd period is one where I am allowed to use one of the bathrooms. I put my hand up.

"Miss, can I be excused to use the bathroom?" I ask.

"You aren't just going to sneak off to touch yourself are you?" my teacher asks back.

"No, of course not" I lie.

"Ok, you can go, but I'm going to have to send someone with you to keep and eye on you just in case. Any volunteers?"

Every hand in the class goes up.

"Amy, you can go" she says pointing to a girl I haven't met yet.

I'm relieved that she didn't chose Sarah or Jessica. They would certainly have made it as humiliating as possible. I'm glad she didn't pick Natasha either. Amy seems content to walk to the bathroom in silence only stealing the occasional glance. After she follows me into the bathroom I try to close the stall.

"I'm supposed to keep an eye on you, remember?" Amy says. "Door stays open."

Amy stands directly in front of the open door as I sit on the toilet and awkwardly try to position my massive erection.

"That's going to make it a bit hard to pee" she says.

I don't respond.

"You can touch yourself if you want. I won't tell anyone" Amy says to me.

I really don't want to jack off in front of her, but it really is becoming a problem.

"Really?" I ask. "You promise?"

"I'll tell you what" she says. "If you let me film it, I'll let you do whatever you want and I won't tell anyone."

That was all the agreement you needed. I close your eyes as Amy pulls out her phone, trying not to think about it. I just think of Natasha playing with her nipples, then of my hard cock breaking through my jock strap, then back to Natasha, then to Mrs. Jones smacking me with her ruler. It doesn't take long. I moan loudly as I erupt. Unable to aim my cum splatters to the floor. I sit, breathing heavily.

"You made quite the mess" Amy says, breaking me out of my post-orgasm glow. "You'd better clean that up."

I bend down to wipe the floor clean, thankful that Amy has stopped filming me.

The walk back to class is about as passes in silence with me relieved not to be drawing any extra attention to myself.