basically, "choppin' it up" means just
shooting the breeze with friends, i.e. conversing and just talking about whatever comes to mind.
Chopping it up can refer to analyzing a situation, such as
breaking it down and explaining it.
Choppin' it up is usually experienced best while having a cold beer in hand. You can chop it up anywhere, in the car, on a plane, in the restroom, or even via text messaging.
"I called my boy and we chopped it up for awhile about last night"
"We didn't have a lot of work to do today, so we just sat around choppin' it up"
person 1: "So,
what do you think about leaving
Thursday night instead of Friday morning?"
person 2: "It's definitely
on the table, but we might have to chop it up first."