The Biology of Music - I fucked my trans substitute teacher

"Do you know why I asked to speak to you?", she asked.
"Because I was passing notes?, I reply sheepishly.
"But you weren't passing notes"
"No...". I am so confused and she is speaking so closely to me now
"Can I ask you a question first of all... have you been staring at my legs"
"No way. What? If I was I'm sorry. I just... They're nice legs...". I am getting a little bit of confidence. There's something happening here. My heart is beating so hard I can feel it in my throat. I swallow hard.
She laughs, and smiles back at me. She has such a friendly smile and a sexy giggle of a laugh. "I saw you looking at my legs. My tights. My skirt. My ass... I saw you looking and then I saw what you were doing. Do you think if you finished you would be better able to concentrate in my class"
"Finish what?" I am not about to admit to this woman I've just met that I am masturbating, even if I am really suspecting there is an energy here.
"Oh maybe I was wrong, but it seemed like you were about to cum into your school uniform trousers. I can think of a much better place for you to cum if that is what you were doing".
Another teacher passes in the corridor, and greets both of us. He looks back and she gestures a hello back. I am supposedly in trouble so I keep my head down. When he turns the corner, she moves her hand onto my waistband. "Do you know of somewhere we could go?"
"Uh, I think the music room might be free". I can't believe how I thought of it so quickly. I can't believe any of this is happening. I don't believe it is.
"Would you like to bring me to the music room. You could eat me out on the piano"
"Fuck yes. Fuck yes. Let's go to the music room. Follow me"

I start leading her to the music room. It's in an isolated part of the school, right on the top floor. There is only music classes on certain days, so it's usually empty. I go as quickly as I can so she doesn't change her mind on the way. We arrive and the room is unlocked. We go in and close the door behind us. She stands in front of me, and looks down at my penis.