The ball is in somebody's court sentence
It is used to tell someone that it is time for them to take action or make a decision.
I have done half of the test for David. Now the ball is in his court.
I have finished part 1. For part 2, the ball is in your court!
We have given him the offer. The ball is in his court.
Turn left or turn right. The ball is in your court!
Being looked after or protected by someone
To give someone a particular responsibility or duty
If something falls (squarely) on someone’s shoulders, it is the responsibility that one have to take.
Used to indicate the responsibility belongs to someone, normally a negative one.
This idiom comes from Tennis: when the ball is in one player's court, it's his/her turn to take action with it.