Fellatio and/or Cunnilingus, what would you say?
What would you emphasize? What would be your few "this works!!" tricks you'd have to share with EVERYONE?
first lessons for going down on a girl. A good trick to start is use your tongue to write the alphabet in cursive on her clit, then try it in all caps. Start slow, and increase speed in response to her body. And one thing that always works for me it taking her clit gently between my lips and lightly sucking and messaging it with your tongue at the same time.
Certainly. There's probably better drawings out there, but Scarleteen site has a good "101" aimed at beginners.
Some things like the difference between circumcised and uncircumcised is a good illustration -- could be by the time someone see someone else's penis, it's erect and the difference isn't as noticeable.
Labeling some things like the sweet spot on the penis makes discussion easier.
Then there's the whole "where the heck is clitoris hiding?" For that, you almost need a model where you can poke around in the folds! Betty Dodson has a bunch of different vulvae illustrated at Scarlet Teen.