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.
Although a tail in motion isn't usually a positive sign, exceptions do exist. For instance, if your fluffball's tail is shooting straight up into the air while it's vibrating and shaking, she is probably feeling giddy about something. If your cat reacts this way upon seeing you, take it as a huge compliment. After all, cats never lie about their emotions -- one of the greatest things about them.