What do they mean by "meep?"

[Twink]

No pics, sorry!

So, we propped THE DOOR open just a crack last night. Enough for Rizzo and Barliman to see each other, but not enough for them to get a paw through with any kind of force. They were pretty good about it. Very little growling or hissing. They’re completely fascinated with it other, and there is a LOT of hunkering and staring. They seem to have gotten somewhat used to the sight of each other overnight. I woke up this morning, and they were sitting on their respective sides of THE DOOR. Somebody—I *think* it was Barli, but this is one instance where I can’t tell their voices apart—was making inquisitive little chirping noises: “Meep? Rrrrrreeep? Mew?” I thought that was a definite improvement over yowling and growling! Neither of them is making aggressive noises any more.

That said, they’re still pretty tense. Swishy tails and all. And Rizzo doesn’t quite know what to make of it when Barli smacks his paw. I think Barli is just a little too eager to play for Rizz’s taste. Rizzo doesn’t trust him yet.

My question is this: how do we know when it’s time to let them interact directly, without THE DOOR? And when we do, should we put them in Barli’s room, or the apartment at large? And, how much hissing and smacking will be normal, and when is it too much, and when should we intervene?

I’m so new at this. I’ve been around cats before, but never more than one at a time! All help and encouragement is greatly appreciated. And, in fact, begged for.