Related Clues:

• *Reveals one's true feelings (or the other way, pater ___)
• Gives things away
• Spills a secret
• Quits clamming up
• Adds to a number, in a way?
• Squeals, in a way
• Fails at secret-keeping
• Poker player’s giveaways
• Unintentionally reveals
• Confesses being no good in MI6
• Gives voice
• Events at an academic conference
• Performs in an opera
• Releases yob that keeps drug stash regularly hidden
• Poker snafus