"Having so much history that bringing out one certain reminder of a joke can trigger laughter," Mitchell says of their fourth rule, Be A Mindreader. Blaney adds that they "Can stare at each other -- [Shay sometimes is] like, 'What do I want to eat right now?'" and she'll usually get it right, like they do in the video.
All through their advice session, you can tell that they appreciate and respect each other, which is one of the most important things to do with your BFF -- and also rule number 6. ?
Watch the full vid below.