When you driving and either you are following somebody unintentionally, or vice versa.
A "Dude that person keeps following me everywhere I turn"
B "Do you think it's a cop or you know them?"
A "No, I think they are just drivestalking me."
This person isn't paying attention to the road at all. He is drivetalking. He needs to get off the phone and concentrate on the road before he causes an accident.