Hi all

I have two cats both female, sisters that are 2 years old, they were 'done' when they were 6 months old, but they some times spray (well i say spray, shake there tails really fast at stuff) all over the house, like underneath the chairs and on the fire place etc.... they arent spraying anything out (i think as it doesnt smell or there isnt any wetness) what are they doing? Do they think they are marking there territory? Should they be doing this? Is it normal?

Bless them, i hope some one can shed some light on this, thanks!!