Related Clues:

• Cat murmurs
• Contented comments
• 'Ooh' companions
• Physical reactions?
• Sounds of comprehension
• Checkup responses
• Doctors hear a lot of them
• Sounds in a dentist's office
• Betrays contentment
• Runs well
• "I see" sounds
• Doesn't ping
• Contented comments from 27 Down
• Oohs and __
• Exam room sounds