How does the baby come out?

I teach music at a daycare once a week. There are seven classes from 1 year old up to preschool, and I spend a half hour with each class. (By the way, why are daycare classes named after animals?) Lately they have really taken an interest in my belly and what is inside. The babies don't seem to notice, except that they don't fit on my lap anymore, but the older kids definitely notice.

They've started asking questions. One asked me, "how does the baby come out?" I distracted that one with something else and didn't have to answer. One kids always wants to know why the baby is still inside. And last week, the best question yet was, "Why are you so fat?" After his teachers and I looked at each other with 'yeah, he really did just ask that' looks on our faces, I said something like, "oh, you've noticed that my belly is getting bigger, haven't you? Well, there is a baby inside..." and this week he kissed my belly button.

That is another thing. They all want to show affection to the unborn, either by crashing into me, or by timidly touching, kissing, or hugging my belly. I'm glad the baby hasn't jabbed anyone yet, and I'm curious what they will do when there isn't a baby inside anymore.