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
Fariha	-	Arabic, Urdu
Rhiannon	hri-AN-ahn (Welsh), ree-AN-ən (English), REE-ən-ən (English)	Welsh, English, Welsh Mythology
Freeman	['fri:mən]
Margarit	-	Armenian
Thalita	-	Portuguese (Brazilian)
Chinweuba	-	Western African, Igbo