I read this and I too have been there.
Yes; reading this account of this group of students talking about reproduction and having there conversation go from sperm to semen sure brought back an incident back when I was 16. We too had been covering reproduction in a class at school and we covered the egg and sperm cells and fertilization, etc. I and my girlfriend of the time were in the class together. After school we went to her house as we often did and on this day we began talking about what we had covered in that class. But this was where the similarities with this other story ends.
This girlfriend went to using the word 'cum' when referring to sperm. She had obviously been around some. I was taken back some when she first used this word. It certainly wasn't a word one would use in our class. She then got into talking about cum and started asking me questions about it. I wasn't sure how to answer her. She asked if it was the white slimmy liquid as she had heard it was and did it come out in long squirts. I was quite shy and didn't know what to say. She then lowered the boom on me telling me she wanted to see my cum! I again was wordless yet beginning to feel excited and getting aroused at the idea of this. I was a 16-year-old teen, remember, and just the idea of this sure made me get hard. She kept up telling me she wanted to see it and I was so aroused about it I told her OK.
She stood waiting and I finally nervously dropped my pants. I couldn't believe the excitement and sensation I was having standing there with a girl seeing my dick for the first time. It was hard as a rock and pointing straight up and bouncing with my pulse. Her eyes were glued to it. I then wrapped my hand around it and started stroking it. She moved closer looking right at it. It wasn't any time at all and I blew. She most certainly got to see my cum as I shot rope after rope of it and some of it got on her skirt. I slowly came down from my orgasm and pulled up my pants feeling a bit embarrassed then. She went to the floor touching the cum and feeling it.
She told me how neat that was and that she now knew what cum looked and felt like. We ended up doing this almost every day after school and I got to see and touch my first pussy and we soon got into mutual masturbation. This felt so good having this girl touching and holding this most private part of my body. I'm sure she felt the same when I had my fingers inside her.
These classes were sure good for one thing at least. They sure got us teens curious when it came to the opposite sex.