lose my balls??
‘You know,’ I said, my hand on the knife, underneath my shirt, ‘if you were me, you probably would.’
The man who’d spoken looked away from me to nod his head at the policeman. The officer saluted, climbed back onto his bike, and rode away.
‘Nice trick,’ I said, turning back. ‘I must remember it, if I ever lose my balls.’
‘You can lose your motherfucking balls right here and now, gora,’ a thin man with a pencil moustache said, showing the blade of a knife he hid in his sleeve.
I would like to know what does "lose my balls" here mean. Thanks.