Declaration of this magic phrase upon observing a Volkwaggon Bettle before its being voiced by one's accompaning passenger in a vechile entitles a person to a warrented, fully justified, and unretaliatable jab in the arm of the accompaning passenger. This rule supersedes all existing laws on assault in all jurisdictions within the continental United States, Canada, and some participating regions of Mexico not under the control of the drug cartels.

when you're hungover as shit after a spending a night drunk as a skunk

An annoying trend in which a person punches another person in the arm after seeing a Volkswagon Beetle (Bug).

a game played during car rides amongst people. everyone looks out the window and the first person to spot a VW beetle, or any VW yells "Punchbuggy!" and punches opponents in the bicep

Punch buggy is a car game played when passengers see a Volkswagen Beetle. When you see that car, you yell "Punch Buggy (color of the car)" And bunch a person in the car. You can say "Punch buggy Blue no punch backs!" that means that the car you called cannot be said again for the rest of the day and you get the point.