A typical yarn would be, while waving a mouse toy on Kato's bed, "You think you can beat me? you think you can beat me? Well I'm in your house, the mouse is in your house. Ooh, it's nice in here. Bet you can't get me. Oh no you can't." Kato leaps and the mouse is whisked away. "I win again! That's one to zero, one to zero. Who's the best? I'm the best! Bet you can't catch me...."etc.
I can't quite work out how Kato knows that this is part of the game, but he does. I guess it is the excitement of someone talking to him and being so involved with the game that they are prepared to be totally ridiculous and abandoned. Cats KNOW when you're into it. In fact, Kato will not accept lazy plays, where the human is flicking the toy while watching tv. He wants our attention...so he leaves the toy, and comes over to us, and either meows in our face, or hugs our leg and meows at us!
As you can see from this Kato the Korat cat video, words are not even necessary to rev up Kato - at around 20secs in, husband man is both tapping his toy, and making ridiculous cat noises before Kato commits to the leap and chase of the lemongrass stalk. I've also heard man-made squeaks and squawks in the midst of other games!