It's Doe, and she heard you

"I know you're in there, John. Open up." You jerk upright as you recognize Doe's voice–who knows what kind of trouble she could get you in?

Mary, as unselfconscious as ever, opens up the door. "Hey Doe! John was just showing me his dick. It's pretty big, see?" she gestures toward your still-still member.

"Yeah, I see," Doe smirks. "Mary, why don't you go get cleaned up."

"Oh, right, yeah! Ms. Stevens will not want to see this," Mary says, wiping some of your cum off of her face with a hand. She gets up and heads towards the sinks at the other end of the locker room. "John, look me up sometime. I'd love for you to teach me some other stuff!"

Doe smiles at you as Mary runs off. "I see you've met Mary. She's pretty sheltered." As you open your mouth to respond, Doe cuts you off. "I'll kill you if you hurt her, John. Anyway, it looks to me like you were breaking some pretty serious rules. Mary's a model student, she'll get a slap on the wrist, but you're new. If I reported you you might get suspended–or expelled." Doe smirks at you again, clearly leading up to something big. "I might not tell anyone about this–if you decide to be a good boy."

"So you're blackmailing me?" you ask. "What are you going to make me do?"

Doe smiles and licks her lips, glancing down at your softening cock.