Definition from Wiktionary, the free dictionary
get (someone) by the balls
- (idiomatic) To have complete control over someone, especially of a woman abusing a man's infatuation with her.
- Too bad she's got you by the balls.
- (Rolling Stones, Short And Curlies)
- If you’ve got them by the balls, their hearts and minds will follow.
- (John Wayne)
to have complete controle over someone