Tail slamming

I have an outside cat, whose name is Topaz, who slams her tail when she lays down. She lifts her tail up, and SLAMS it on the ground, enough to hear the noise of the bump 10 feet away! She does it when she happy, affectionate, loving, tired, playful, depressed, mad, apprehensive, and even when she is being petted! She does it at night, during the day, and anytime in between! At first, I thought she was just scared of being in a new place, (my grandpa kept her in his house for a while, but it didn't work out... she was too wild for him) but we soon found out she did it constantly, and she still does. Does anyone else's cat do this? And, does anyone know why? I mean, it's not a problem or anything... I'm just curious as to why she's doing this.

Thanks!

(This is the only pic I have of her.... she doesn't have any kittens anymore)

I used to have a cat that would do this when he was mad or frustrated. He would sit there glaring and his tail would go whop whop whop whop loud enough to hear from some distance away. He never did anything else about his frustration, just 'whopped' his tail against the ground.

He didn't do it at any other time, though.

Kathryn

Well, that's what I was thinking.... cats wag their tails like that when they are mad... but, Topaz does it constantly. She'd do that and purr and close her eyes, and be all loving at the same time!

Pfffttt you should see Rosies when she's fed up of me stroking her!.

Thats the warning i get to stop!, and the minute i do the tail stops