I just found this on my desk.
Youngest sister writes "I am not happy"
Older sibling replies "Have you ever smelled my bum?"
Youngest sister replies "No! You are weerd"(sic)
When I asked older sibling to explain - he said, "I was just trying to make her smile and it worked. She was happy after that."
I blame it all on the bad influence of my older brothers. I fear for my daughters. I know what it is like.