Possible Clues:

• Self-critical part of the mind
• Third of a Freudian trio
• ID checker
• Behavior modifier
• Moral part of the (Freudian) unconscious
• One-third of Freud's psyche
• I follow exceptionally good, strong, unconscious, inhibitory mechanism which criticises itself
• Say nothing after policeman gives a piece of his mind?
• Freud's conscience
• Drink before work which makes one feel guilty