Princess P & I talk about boobies.

"Mom. you need to comb my hair!"  exclaims Miss P as she rounds the corner into my room where I'm still dozing.
"rrf? shrr.  k.  I'm up.  I'm up."
"It's okay mom.I'll let you get dressed first.  You need to put on that thing that holds up your boobies. "
"Gee.  thanks."
"It's okay mom.  As you get o'der, they start to fall down.  Wow, you're boobies are big."
"Yeah, well, I keep hoping they'll start to shrink, but they haven't done that yet."
"No, that's when you get old, like Grandma.  Hey, why are you putting that white stuff on there.  Ohhh, that's right powder keeps your fat dry."
"Uh-huh.  So I don't get infections and nasty red marks under there.  You had to do this too when you were a baby, because of all the folds in your neck and legs."
"I did?"
"Yup."
"And when I grow up, I'll need to protect my boobies."

And that, is what sex ed for a five year old looks like.