This mistress wanted to test whether this guy was ready to do anything for her as he had been telling her for as long as she could remember. So she gagged herself as he watched and she could see how shocked he was. And after she had puked into a bowl, she poured it into a glass and told him that since he wanted to do anything for her, she wanted him to drink her puke. He was visibly shocked and wondered why she would make him do that. But he honored his word by drinking it. She believed him.