Related Clues:

• Super
• Backrub response
• Sound of satisfaction
• On edge
• Physical sound?
• 'What a relief!'
• 'Don't stop'
• Sigh of relief
• 'Won-der-ful!'
• ''That's it!''
• Sound of relief
• Sound of contentment
• ''That's the spot!''
• 'That's nice!'
• Reaction to a back rub, maybe