Related Clues:

• Make a slip
• ... thunder
• Bedtime "Land"
• OK sign, maybe
• Indicate uh-huh
• Signal at Christie's
• Summon a servant, maybe
• Nonverbal 'yes'
• "Go ahead" signal
• Nonverbal assent
• Be a good fan
• Indication of a green light
• Sound from Thor
• Acknowledge silently
• Try to induce an encore