I am so glad you asked that! I have been wondering myself and since I do this at work and play at home, I don't think of it when I am skulking around here.
I am a huge fan of Rogues as my two favorite characters are a Bard and a Thief. However, I have never really figured out the backstabbing part of it all. Fortunately, I am still early in the game (chapter 2 -- right before Firkgaard!) and haven't really needed the multiplier for the backstabbing just yet.
