I've trained him well, with a collar and leash, and by demanding chastity and submission. When he gets hard in response to my seduction, I reward him with positive reinforcement.
But if he becomes aroused by porn, or some scantily clad sexpot, the consequences are decidedly... negative.
The vixens and cougars might tease and flirt with him. After all, he's a desirable man. Yet he remains devoted to his mistress. His erections are now for me alone.
I'm the one who doles out punishment and pleasure. I'm the one who holds the key to his cage.
