A little girl runs out to the backyard where her father is working, and asks
him, "Daddy, what's sex?"

So, her father sits her down, and tells her all about the birds and the bees.
He tells her about conception, sexual intercourse, sperms and eggs. He tells
her about puberty, menstruation, erections, wet-dreams...

He thinks, what the hell, and goes on to tell her the works. He describes
masturbation, oral sex, group sex, pornography, bondage and discipline,
homosexuality, sex toys, etc...

The girl is somewhat awestruck with this sudden influx of bizarre new
knowledge, and her father finally asks, "So what did you want to know about sex
for?"

"Oh, mummy said lunch would be ready in a couple of secs..."