Possible Clues:

• Sass from a therapist?
• *Subconscious revelation
• *Calling your boss "Mom," for example
• Revealing, though unintentional, expression of a sinful pride, perhaps
• Spoken error revealing unconscious thought
• Slip of the tongue, revealing unconscious thought
• One trained to analyse piece of paper is revealing error
• Revealing accident by word of mouth?
• Sort of shrink underwear to give a revealing view
• Words revealing unconscious thoughts