The ball is in your/somebody's court - Idioms by The Free Dictionary
the ball is in your/somebody's court
the ball is in your court
COMMON If the ball is in your court, it is your responsibility to decide what to do next in a particular situation. We've made him an offer but now he has to decide whether to accept: the ball is in his court. Note: This expression refers to the game of tennis.
the ball is in your/somebody’s ˈcourt it is somebody’s turn to speak, act, etc. next: I’ve given them a list of the changes that I think are necessary, so the ball’s in their court now.