Rose loves snuggling with Nahum. When she's alone in the cat bed and sees Nahum approaching, she makes an unique sound, like she is inviting him to snuggle with her. She is actually calling out to him. And often he accepts the invitation and snuggles in with her. I have not heard her use that sound any other time, she reserves it for Nahum only as she never calls out to Willow or Theo.
I hope this is something that sticks with her forever, because it is sooooo cute. I might need to start a list of all the cute things about Rose.