The ball is in your/somebody’s court
Definition 1 of 1
Pro Tip 1/3Tennis Origin
Imagine a tennis match where you wait for the other player to hit the ball back. 
I've sent the job application; the ball is in their court now.
Pro Tip 2/3Decision Time
Use it when someone needs to make a decision or take a step after you’ve done your part. 
You've heard my side of the argument; the ball is in your court.
Pro Tip 3/3Shared Responsibility
It highlights that now it's the other person’s turn to share the responsibility. 
I've planned our last three dates, the ball is in your court this time.