It can be a sign of vulnerability and fear. Declare to yourself: "I am strong and healthy, I accept myself such what I am". Whether there is a sphere of life in which you feel the impotence? (It concerns both to men, and to women.) What forces you to consider itself as the impotent man? Relax and reconcile with yourself. Life exists in order that to enjoy it. Enter yourself and reunite with a source of the personal force.
To the man of powerless not to see, be able to make a coition - from others to get support.