The sound of cat noises, intensely engaged in tangling. That's be good, get Piazzolla to write them a tangle. It's just a thought
My own cats are getting old. And are almost out of the range for that kind of behavior. They were kittens one time, of course, small and tumbly and playful. I drank Coke back then and both would fit in a 12 pack box, easily.
Now they're big old cats, one bigger than the other, so they don't fit anymore. You couldn't fit one in.
My biggest cat is getting arthritic maybe, I don't do diagnoses for a living. He's definitely not doing what he used to do, which would be jumping up on the counter, tipping over the garbage can, etc. Their food is "up" to keep the dog out of it and he can't even jump up there any more -- maybe he physically could but he doubts his abilities. I give him a boost.
They used to do this whole thing of licking each other, then it became a hissing fight after about 20 seconds of that. Every time.