It turned out that I didn't have to wait till then.
As we walked into Biology you grabbed my arm and told me to come and sit at the back, so we could talk. We slid into two chairs in the corner, but before you could say anything the Teacher started to talk.
As we got out our work and started to write, I couldn't stop looking at you out of the corner of my eye, couldn't stop remembering that I had just a little while ago, been stroking and feeling you naked underneath me. That those hands holding the book in front of you had been caressing my body. I leaned back to stretch and caught sight of your crotch, and saw your big cock just laying there, pressed up against the fabric of your trousers. You always did wear tight clothes; you had a small waist but your firm buttocks used to stretch anything thing your wore tight across the front.
I suddenly felt the urge to do something risky.
I lent back forward and continued to write with my right hand, and put my left on your muscular thigh. You looked up and around, worried someone might see. Once you realised no one was watching you smiled at me and put your hand on my thigh, gently squeezing.
I think you thought that was the end of it but I wanted more.
Still writing I moved my hand down into your crotch, holding it just above your cock. You froze as I slowly began rubbing you through the fabric. You looked a bit worried about being caught, so I stopped and went to take my hand away, but you grabbed my wrist.
You looked me straight in the face as you put my hand back where it was. As I started again you opened your mouth slightly, giving a silent moan of pleasure. As I stroked harder you stared at the book in front of you, concentrating on not drawing attention to yourself. My hand shook as I got a bit braver and decided to unzip you. I reached in and felt your Calvins. I moved your cock so that the full length when erect would go down your trouser leg and not show. I could imagine the head somewhere near your knees but couldn't reach so contented myself with squeezing the thick base, wrapping my fingers round your shaft. As I squeezed harder ad harder I could feel your cock throbbing, ready to burst. I lent back slightly to look at the full length bulge, and realised there was a dark mark where your head was oozing precum.
I smiled and worked faster. I wanted to make you cum, there and then, surrounded by all our classmates. The idea turned me on and I wanked you hard. As you came your cock bucked in my hand, you held your eyes shut, repressing your moans of pleasure. Lucky you had come a lot in the changing rooms, so you didn't soak your trousers like you might have done, but it was still an impressive load that showed through your trousers.
The end of lesson came and we slowly packed away, waiting for the rest of the class to file out the door. As the last one went out the door you grabbed me by the tie and pulled me in for a hard kiss.
"You're gonna pay for making me do that,"you whispered.
You straightened up and, using your bag to cover the mark on your trousers led me out the door. I couldn't believe you were gay and I was getting to enjoy that beautiful body of yours. I couldn't wait to tell people, maybe even go out on a proper date...