Marijuana, the most often used illegal drug in this country, is a product of the hemp plant, Cannabis sativa. The main active chemical in marijuana, also present in other forms of cannabis, is THC (delta-9-tetrahydrocannabinol). Of the roughly 400 chemicals found in the cannabis plant, THC affects the brain the most.
Cats 'vibrate' when marking territory-spayed cats can also 'dry' spray. Spayed male cats urine doesn't smell. They swish their tales as a sign of annoyance or anger. If the tip of the tail 'trembles', it's quite often a sign of being 'unsure' about something. Source(s): Cat owner.
Usually when a cat swishes its tail they are expressing their emotions. For example, when a cat is angry he or her will swish their tail rapidly, if happy the cat will barely or will not swish its tail. It all depends on the cats genetics or personality.