Julia Sweeney talks to her nine year old daughter about how frogs reproduce, and when your nine year old keeps asking deeper questions, they lead to less than comfortable places. With hilarious consequences!
Personally, I intend to follow the example of my brother/sister-in-law and leave Mummy Laid An Egg lying around. Terribly informative, and embarasses guests no end.
Original post on Dreamwidth - there are comments there.