Yeah, uh... it's a two-day party, 'cause that's just how we roll. Uh, so, if you want to swing by, you know, it's casual. (how I met your mother S1 EP1)
I can't find the meaning of roll from dictionary.
is this the same as roll in rock and roll? or roll in winter roll around?
* Not a teacher
It means something like that's how we do it.