Why do cats like to rub against people and sweep their tails?
When a cat rubs against someone, it's a sign that it likes and wants to be close to that person.
Cats often rub against objects in their familiar environment, filling the house with their scent, which makes them feel very safe and secure. 
If a cat brushes its tail at you, it means it wants to play with you, is not wary of you, and wants to interact with you. Don't worry or be nervous.
You should spend as much time as possible playing with it and interacting with it to build a good relationship.
