be (sitting) on (one's) tail

To follow close behind someone or something. Why is this guy sitting on my tail when I'm already going over the speed limit? The cops are definitely on our tail now—we have to turn ourselves in!

Common Names:

Name	Pronounced	Usage
Munro	-	Scottish
Gerolamo	-	Italian
Sharon	['ʃærən]
Lavrentios	-	Greek
Marlena	mahr-LEEN-ə (English), mahr-LE-nah (Polish)	English, Polish
Cara	['kærə]