An action were one will bob their head back and forth in a ridiculous manner while listening to music, and ignoring the outside world.
Common cause for bird facing is unknown but studies may have a direct link related to music such as nickelback, coldplay, justin bieber, and many more.
person1: "that chick is totally bird facing right now"
person2: "like a boss, she is probably going to have a headache"
when bird facing one will appear to have similar movement to that of a pigeon.