Years ago I bought a pack of stickers. This is how I am using them.
Around the release of each new Fast and Furious movie, you will notice an increase in the amount of cars (usually “tricked out” 2003 Honda Civics) driven by leaning drivers — drivers who shift their body and head in such a way as to let other drivers know what’s up. Here’s a printable guide to what the lean means. (click to enlarge)