Nothing like making cake

There was a little girl and her mother walking through the park one day, and they saw two teenagers having sex on a bench.

The little girl says "Mommy, what are they doing?" the mother hesitates then quickly says "Umm... they are making cakes. Now come on, we'll go to the Zoo."

At the Zoo, the little girl sees two monkeys having sex.
Again she asks her mother, "What are they doing?"
And again her mother says "They are making cakes. That's it, we're going home."

The next day the girl says to her mother "Mommy, you and Daddy were making cakes in the living room last night, weren't you?"
Shocked, the mother says "What? How do you know?"

She says"Because I licked the icing off the sofa."