Related Clues:

• Good engine noise
• Stink; buzz
• Throaty seductive sound
• Mog's murmur
• (Thanks for rubbing my belly!)
• Garage mechanic's goal, maybe
• Sound of a happy tabby
• Keep one's mouth shut?
• Contented cat's sound
• Sound of a Jaguar
• Contented cat’s sound
• Happy Himalayan’s sound
• Make music on a kazoo, say
• Murmur in a cat cafe
• Noise from a beehive