I've name changed for obvious reason.
I'm looking after DD 3+6 and her nearly 4 year old fried today.
They've been doing lots of drawing. I just went to look at some of them and asked DD's fried what the pink oval and sausage like shape were.
Her response was "its mummy's vagina and daddy's big penis"
Should I say anything or do you think its just natural curiousity about "bits".