Yeah, same here - I'm not a mother and don't want to be a mother, so it would never even occur to me that I could or should give that kind of advice. I know it sometimes drove Mum bonkers when my dad's sisters, who were unmarried and had no children, kept telling her how to raise us.

Aunting advice I can give, though (i.e. advice to aunts). I'm a pretty good aunt. And high up on the list comes: You're an aunt, not a mother, so while it's obviously OK to have different house rules for your niece or nephew compared to how they do things at home, you shouldn't ever try to imply that their parents' way is inferior to yours. Because it probably isn't, just different.