Cats flicking their tails while sleeping may be just unconscious behavior, which may be related to their dream activities. Like humans, cats also dream, and may be chasing, playing, or exploring their environment in their dreams. At this time, the wagging of the tail may be a natural reaction in the dream.

In addition, the wagging of the tail is sometimes a sign that the cat feels relaxed and comfortable. Just like humans may turn over or adjust their position during sleep, cats may also adjust their sleeping position by wagging their tails to find a more comfortable position, so owners don't have to worry too much.