My patient's treatments are about to get so much more difficult. He's already so hard from being free from the chastity device, face covered with my ass, that I'm able to do anything to him. It's time to sound him and show him that his cock is not just for jerking off. It's my hole now, and I'm eager to control it internally. I glide the urethral sound down his cock hole, proving to him that the training is working: he gets hard at what I want him to get hard to. And if I want him to get hard to a metal rod shoved down his cock, then so be it.