This phrase means a group of five people who all dab and congregate together at Mexican restaurants... Preferably with tequila shots.
This gang will hangout and roam the streets at night without actually doing anything. Within the gang, there is typically a korean, a moodi, and a hungarian dude who thinks he is funny. But he is not.
WARNING:
If you see a Dab Gang coming, stay clear!
Person 1: Wow! Did you see that Dab Gang?
Person 2: Yeah! I wish I could hang out with them!