Cat Tails

Sometimes I wonder about stupid things, like how much control cats have over their tails. I wonder about this because we have two cats and their tails are pretty funny sometimes. Sometimes they keep them curled up around them when they sit, and sometimes they stick them out. Sometimes they let them twitch and sometimes they hold them absolutely still. I know that people say that you can really tell a dog's emotion from their tails, but I think that you can with cats, too. But that leads me to wonder, how much control do they actually have over their tails?

I like to play with the cats' tails and I don't think (in fact, I know for a fact) that they don't appreciate it very much. I like to pull their tails away from them if they're laying by me with their tail wrapped close to them. I usually get glares (the cats glare at me an awful lot), and they pull their tail back, and then I pull it away again, and we do this over and over again until I can see that the cat is about ready to attack me and then I leave them alone for a while. 

I wonder, when their tail is twitching as they're "stalking" the pink "mouse" or the fuzzy ball, or each other, if they're consciously twitching it, or if it's just something that happens.  It's probably like the breathing and blinking is for humans. Our bodies do it naturally, but we can control it if we want to. 

I could probably look up how much control cats have over their tails, it would probably be pretty easy to find out, just a Google search or something, but I think it's more fun to wonder.