Related Clues:
- Contented feline sound
- Fire on all cylinders
- Contented rumble
- Happy Himalayan's sound
- Speak softly with contentment
- Back up expensive car -- the noise it makes!
- Sound pleased to turn up with expensive motor
- Low drone
- Sing with your mouth closed
- Car or cat sound
- Sing a wordless tune
- [Your lap is nice and cozy, human]
- The response of the fat cat perhaps to jeer from perjurer
- 'I am VERY happy you gave me this catnip'
- Sing along without words