A little girl and her mother are walking through a park and see two teenagers having sex on a bench. The little girl asks her mother what they're are doing. After a moments hesitation, the mother replies "They're making cakes."

The next day the little girl and her mother go to the zoo. The little girl sees two monkeys having sex, and again asks her mother what they are doing. The mother again uses the same answer "They're making cakes."

The next morning the little girl says to her mother "Mummy, You and Daddy were making cakes on the lounge last night."
The Mother replies " How do you know?"
The girl says "I licked the icing off the sofa!"