It will display in the lower left-hand corner of your screen, and often overlap your companion character window. I see people asking all the time how to do this or did not know this existed. --- http://img443.imageshack.us/img443/818/firstwaveg.png
It has to be programmed into the game. It is not a function that exists in all games. But when it does exist..my experience has been it usually involves the "f" key...be it "ctrl-f", "alt-f" or simply "f".