mind your ps and qs

Mind your ps and qs is a common catch phrase often spoken by a parental figure such as a parent, grandparent or other close family member, to children who are not showing good manners or are behaving badly. Mind your ps and qs is another way to say mind your manners, mind your language or be on your best behavior. It originates from the proper way to write ps and qs both in lowercase and uppercase.