Aura is something like currency to this gen-z world, in which if you gained aura, it means you did something which is appreciable. The more aura u get, the higher or rare to do that thing. If you did something stupid, then the aura will reduce.
When you gain aura: Like rizzing a girl or doing something cool or helpful
When you lose aura: When you step on shit or cow dung. or when you do something silly or stupid.
When someone has the characteristics of a chill guy. And a nonchalant dread head. Practically when someone is known to be very popular and good to hang with. Or just to say someone is really chill and cool. Also used as points