Chilling with your peoples, kicking back relaxing or just enjoying yourself for the moment. Also can be used to tell somebody to do the same, or to simmer down if they're being too pissy or aggressive.
Ian: So are yall easing at my place tonight or what? I'll smoke out everybody here, my treat.
Tino: Yeah man let's go over there, come on guys hurry!
Ian: Ease bro, ease... We'll get there when we get there.