Eli5 why grown ups do not fall down from the bed?

Question

I am wondering why small kids ( even a few years old) fall down from the bed while changing their position but bigger children /adults do not, no matter how much they move while sleeping?

In: 2276

Answer 1

When i was a baby, my mother woke up one night after hearing me cry in my crib. I was in the same room.
She was reaching for the bedside lamp and couldn’t find it. She had fell out of her bed.