When my daughter was a baby we played a game. I would smell her head. Baby's heads smell like caramel - I don't know why, they just do, but it is wonderful. I mention this often, to the point where my son would tell complete strangers, "My sister tastes like caramel."
So I would hold my daughter in my lap and say, "I'm gonna eat your baby brains! Yum, yum, yum!" and gently gum her head.*
My son walked in during a session. His jaw dropped, his eyes were wide, and he yelled, "Daddy! Don't eat my sister! Save some for me!"
* Tales of parents eating children ancient and are clearly an expression of an archetypal behavior. Perhaps the most famous example (if you are a dork) is how Zeus and the other Greek gods were devoured by their father Chronos. There are many theories about the origins and meaning of this behavior. But if, as I theorize, most baby heads smell like caramel, it would explain a great deal.