I only see NY nikkas doing that. I saw nikkas running the aisles watching Def Comedy Jam. I ain't think nothing about it growing up till I started hanging around NY nikkaas in NC and watched them run a fukking obstacle course everytime they laughed. Running, jumping, poking you, grabbing your shoulders shaking you, running into you when they circle back around and shyt. You got keep your forearm up so they stop running into you.
NYC nikkas laugh like
Dame and Burke at the beginning of Bring it On and it be a knock knock joke.