How does the baby come out?

[Middledistancerunner]

My four year old is asking about how the baby comes out of mummy’s tummy?
Can any recommend an age appropriate description?
I’m stumped.

I said "when it's time to be born my tummy will start to squeeze and squeeze and the baby will come out through a special hole."

O told my daughter it comes out of my tummy

My ds asked Dd when he was about 4 and she was 14. She was caught off guard and told him I'd poo'd him out. He thought it was hilarious and doesn't want to listen to the real explanation as anything to do with poo is much more interesting.