Disclaimer: I know in general society the contents of this thread aren't at all acceptable but it's mostly hypothetical. So just stick with me on this 
I know there isn't much chance of doing this in most schools, there might be a slim amount where it could work. It's not something I'd really agree with but still.
If it was possible and allowed, would you be a real life sex ed model to a classroom full of young teenagers?
What I mean by that is stand in front of the class fully nude, while they get a good look at your body. If it's a same sex school, you would be of the opposite sex. If it's a mixed school, you might be with a nude partner of the opposite sex.