the ball is in your/somebody's court
the ball is in (one's) court
One has the responsibility for further action, especially after someone else previously held responsibility. The phrase originated in tennis. Well, they invited you, so the ball is in your court now. Do you want to go out with them or not?
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.