Ball Bashing

My slave is one of the silent ones. No matter what I do to him, he never makes a sound. I like to hear squeals and groans and gasps of ache and surprise. So I decide to give his useless balls some extra attention in the hope of getting a yelp out of him! Tied to the cross he can do nothing to stop me teasing him, tormenting him and inflicting whatever I wish upon his balls. Will he squeal? I hope .