Possible Clues:

• Move like a butterfly
• Move in a breeze, as a flag
• Bet a butterfly can do it
• Say this at last with the wings
• Bet
• Fly like some insects, or bat
• React to a breeze, as a flag
• Betray nerves, having bet
• Informally a slight gamble as on a horse
• Fly unsteadily; small bet