Let me tell you a tale of a tiger’s tail.
Almost a meter long, the tail can help the tiger balance while chasing a prey. They use their tails like sprinklers on hot summer days to keep their body cool. Tigers also use the tail to mark their territory with liquid. This marking can last for as long as 40 days. The smell can encourage (for mating) or discourage (to avoid conflict) another tiger to enter that territory.
Tigers have various methods of communication. Most obvious one is the different sounds a tiger makes (like purr, growl, hiss etc.) But even the tail helps them to communicate. A droopy tail means relaxed tiger. Raising the tail and waving gently means friendliness. Twitching the tail can mean aggression.
Look at subadult tiger's tail in the pic.. I think he is showing playfulness, what do you think what his tail is saying?