tail shaking means what?

It's just me again with another question. We have 2 female cat's one is friendly and the other needs TLC which we are giving. Today Rusticat came and sat with me and let me brush her, Pokie always let's you handle her. By the way we have only had them about 3 day's.My question is: Rusticat puts her tail up and shakes it quite a few times. What's it mean? It looks like her tail is having spasams.She is spayed, is she marking territory or being nasty? Please help, this is new to me.

They usually do this when they are spraying, however, if nothing is coming out, then it's a sign of excitement. I have a girl who does this when I walk in the door and start to pet her

One of my females does this too whenever she is real happy. I always say she is being my little "jiggly-tail kitty" when she does it. So, be flattered that she is so happy to be with you!

I have a mother-son pair who both make "happy tail" when they are especially pleased about something.

my Loki also does the jiggly tail, butt squeezing, rear legs stomping thing when I come home from work!!

My Pepperpot does that when she is excited or overly stimulated. Even though she is fixed, she sometimes also excretes stinky fluid from her hind end when she does this. She normally only does this when my husband is paying attention to her (daddy's girl)or we let her outside.

Mr. Fitz does the same thing when he gets really excited--He'll start running around like a maniac and then stop and his tail is straight up and shaking--pretty funny to see, always makes me laugh!