Ways to discover a Potterhead classmate: (Joke)
1) Say Robert Pattinson had a better role in 2005 than 2008-2012
2) Say "Always." on a slow,flat, cold, tone.
3) Say "Diagonally" the way HP does.
4) Mention: Tessa Netting, Snapple and Butterbeer.
Lastly, 5) When someone says "Isn't Harry (Styles) attractive?", you say "Harry (Potter) is already Married! Don't commit a sin!" Then see who just stares, smile or quiets down.