the D thing is basically what is called a "reality check"....in dreams, things change, morph, and go crazy...telling time is hard, and words on a page always change around...By looking at the D on your hand throughout the day while youre AWAKE will become a habbit. Then hopefully relying on chance becuase habbits carry over in to dreams that in your dream you will look at your hand to see the D, which may change or be weird. This will signal you that you are in a dream and you can then try to take control to do what you please...lucid dreaming is the shit