Father teaches daughter about baking cakes.

A father takes his daughter to the zoo. They come across the monkeys and see them mating.
Daughter: Daddy, what are they doing?
Father: ... umm they're baking a cake.
Daughter: Oh ok.
Then they come across giraffes mating.
Daughter: Daddy, What are they doing?
Father: They're baking a cake as well.
Eventually they come across elephants mating.
Daughter: Daddy, are they baking a cake?
Father: Yes. That's what it is called.
Daughter: Oh ok.
They go home and the next morning the daughter wakes up her father.
Daughter: Daddy, were you and mommy baking a cake last night?
Father: ...Yes ... Why?
Daughter: Because I licked off all of the icing.