When a slave has empty balls, there’s hardly any use for him anymore. The one exception I’ve found is that it gives me to opportunity to truly harm a dried up cock and balls. He’s got not juice left, but that doesn’t stop me from encasing his extremely sensitive cock with an industrial vibrator. He squirms and whines as the vibrator turns pleasure into pain. I few squeezes and slaps to his cock and balls are all he needs to lose the ability to stand. I guess there’s still fun to be had even when a slave is all dried up.