How to explain pregnancy to a 2 year old?

Kayella

I'm 23 weeks pregnant with my second son and my first is 2. He seems to understand pregnancy but not that I'm pregnant. (He'll point at pictures of pregnant ladys bellys and say "baby", but just doesn't acknowledge that I'm pregnant) I don't carry very big so I think thats part of it and its very hard to get anyone to feel the baby kick on time. I've read books to him and tried finding a good youtube video to show him. Anyone have advice for me?