Mistress Betty realized that this guy was into asses and she had a great one. She chose to mess with him by showing off hers and the guy could not believe what he was looking at. He thought he was looking at the finest ass he had ever seen in his life and he could not stop staring. He found himself at her mercy as she did whatever she wanted to him.
Mistress Nikki and mistress Sara wanted to have fun with this loser and that is what they did. They had fun at his expense by making him lick their assholes and nowhere else. They had fun kissing each other and playing with each other's pussies as he licked their assholes. It felt so wrong and so right at the same time and they had the pleasure of a lifetime in the process.
This mistress wanted her butt worshipped and she knew her slave was the best bet for the job. She did not have to beg him and she knew he had to avoid pissing her off. She was also not sure whether she would like it and that is why she had him do it. Then if she loved it after he did it, she would open it up and have other guys do it as well.