Dave: Thanks man, coz try-hard gangsta pants are just how i roll. *hi5*
Johnny: *rejects hi5* Your a nerd
Dave: Yeah, but thats how i roll.
Johnny: *rolls eyes and walks off*
Jess: Sarah, your such a skank, hitting on teachers is the most disgusting thing out.
Sarah: Well thats how i roll.
it means "that's how I do things, if you don't like it, too bad. I am an independent person and I scoff at your preconceived notions of society."
(Jack Black punts Baxter, Ron's dog, off the bridge)
Jack: "That's how I roll"
A: "Fool shoulda known....That's how I roll."