What a member of a group would say to suggest that some behavior is the group style, or that it's the way they usually do things. for example What someone would say to insinuate that it was their style, or that it was the way they usually do things. "Yo man so did you already hit it or what?" "Yeah, you know that's how I roll."

There are many variations of this. How we roll and How we do = usual behavior.