Explaining birth to young children

Danielle

How do others explain giving birth to young children. I'm having a home birth so my son will be there and the only way I can explain it is having a big poo that won't come out so mummy has to squeeze and push so hard it hurts. How else can you actually explain this.

I have visions of him telling everyone I had a poo instead of a baby or even worse, been scared to poo himself.

Thoughts?