wig wags 

strobe lights that are usually placed in the grill and tail lights of unmarked police cars in lieu of overhead lights.

He didn't know an unmarked car was following him until he hit his wig wags.

wig wags by duke Wellington about the apartment on park street May 5, 2007

Wig Wags 

Repeatedly flashing your high beams when approaching a stop sign. This automatically gives you the right of way and you don't have to stop

Jon- "Dude you're gonna run the damn stop sign ya jackass!"
Pat- (Flashes high beams) "No worries. Just used the wig wags. Those bitches can wait"

Wig Wags by PatNig May 6, 2011