>>4730It's a Japanese idiom for stingy people.
From what I understand, it's because if you have a small butthole, you can only let out small amounts of poop at a time. Similar to how a stingy person only lets out small amounts of money/information at a time.
So at some point, saying that someone has a small butthole became a (rude) way of implying they are a stingy person.
