Gave them the Goldenballs scenario: They can either split the punishment evenly. Or try to get one of them to endure the whole punishment. But if both pick that, they both endure it for double the time.
You know you love this my sweet pet. Admit it. Tell your mistress how much you love it. Beg me for more. Tell your mistress your purpose. Disobedience will get a slut punished.