I heard about this idea and might give it a shot over the next few weeks.

The idea is that in your dream body, on one or both of your hands (Or anywhere, really - I just say hands because you tend to notice them first), you have some sort of 'tattoo' - a symbol of meaning to you. You can only see it when you're dreaming, so it can be used as a reality check to become lucid.

Has anybody done this before, and if so, had success?