They're talking about "feeling out" the opposite of every emotion and thought for the benefit of being harmonized within yourself...free of mental/emotional anguish over uncovered territory within the inner self. I wouldn't stress too much about methods of doing this, the method is not as important as the understanding that any thought or emotion's shadow side, is more than just a distortion of itself...it IS itself. Once this is thoroughly explored and digested within the self, it becomes a lot easier to "see" just how connected everything truly is in this world.
Godspeed!
Godspeed!