| Another in a long line of well intended admonitions that parents use with small children. It is meant to put a smile on a child's face at bedtime and encourage them to snuggle up and go to sleep. Instead this warning about unseen insects that may or may not be in their bed, about to chew on them, often backfires.
Try telling your 6 year old nephew you were just kidding. And no, they do not know what a euphemism is at that age.
Don't tell a child this on the same night that you have them sing these lines:
and if I die, before I wake... | 
