This occurs when you slip on a banana peel cock first into your best buds anus whilst immodestly pulling out and flinging the leftover dingleberry off your penis right in the flow of traffic.
I totaled my car when a brown paper bag hit my windshield.
Brown Paper Bag is a trucker's term for an unmarked police cruiser commonly heard over the CB Radio. If there's a brown paper bag and he's drinking it, that means said cop has got somebody.