Normally a juggling metaphor that is part of the reference to “too many balls in the air” referring to the idea that there’s a lot happening all at once, but can also refer to a person who is gutless and whose balls have fallen off and floated away.
I was talking to the boss the other day when I looked up and saw his balls in the air, just slowly floating away into the sky above us like little hairy helium balloons!
Somebody else has cornered you into a really tough situation, where you must now make a major decision between two things neither of which you want in the least.
They had his balls in a vice: either take the pay cut they were demanding from him, or be fired.
When someone wants to ask someone out, you put "the balls in the pants". Mostly used for girls who want to ask out a guy. Can also be used for a guy who has been longing for a girl for a long time but doesn't have the balls to confess.
Variations can be just saying the phrase, or putting super balls in each pocket to give you courage.
Jocelyn: I really really really like him but I can't tell him. What if he says no? What should I do.
Jasmine: I think it's time for you to put the ballsin the pants.