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.