Related Clues:

• A stroke of the cat may produce it
• Pong
• Sound (of business?)
• Sound of a contented feline
• Sound of a happy cat
• Sound of happy cat
• Sound of happy animal
• Sound of a happy mog
• Sound of cat
• 4's sound
• Drone — stink
• Say sexily
• Fail to know the words, maybe
• Sounds like the cat's got its tongue, perhaps
• Sound of a contented cat