A phrase that can be used as an exclamation when no other phrase will do, or as a question by someone who's really confused. Typically used as an extra addition to a statement/question, though sometimes used on its own.
Not to be confused with wtf or ftw. Possibly originating when a gamer wanted to to mix things up (or was so mad s/he messed up saying wtf.)
When the guy next to me in my chemistry class saw what would be on the final, he yelled, "They expect you to remember crap from the beginning of the semester?? TWF!"
"I shot that guy in the head three times, and he still turns around and kills me?! TWF?"