Hi there - what type of litter are you using i.e. wood based, grit based?
As for the tail lashing - my cats tail lashes all the time - happy or angry and she too lays on it or if we hold her we do it tight so its not lashing at us. Although in most cats its a sign of anger if they do it all the time there's nothing much to worry about other than you can't tell when she is really hacked off with you.
Remember as well despite you getting to grips with her, she's the boss and its her perogative to change routine at random/suddenly refuse to eat food she has previously loved/wake you up at all hours purring loudly and just generally turn the routine of the house around until it suits her just purrrfectly!