Take a drink: Whenever someone is accused falsely of anything

Take a drink: Anytime someone mentions the "chamber of secrets"

Take a drink: Anytime someone says "Slytherin"

Take a drink: Whenever anyone uses magic

Take a drink: Whenever the flying car is seen or talked about

Take a drink: Anytime Draco gets in anyone's face

Take a drink: Ron Weasly makes his weird scared frowny face like below

Add a rule!