Bound and gagged, the slave kneels before his Mistress, eyes wide with anticipation and fear. She strokes his chin, "You're going to learn today what it means to serve a true Femdom." She grabs his balls, squeezing hard. He winces, but she just smiles, "This is nothing." She attaches a CBT device, twisting the screws tight. He groans as she leaves him like that, returning later to find him in tears. She laughs, "Let's really get this training started." She proceeds to bust his balls, hard, leaving him a sniveling, grateful mess.