Possible Clues:

• What Des might see to do, being not at all happy
• Show you're 18-Across
• "One for all and all for one," e.g.
• Megahit by Johnnie Ray
• "Fore!" for one
• Yip or yelp
• 1951 Johnnie Ray hit
• Be a sore loser, say
• Make a plea for sympathy, maybe
• Clamorous partner of 13-Across