Mistress Gaia wanted to dominate this couple for being dishonest with her. They were cons and she did not want to associate with such people. And that is why she made one ass fuck the other with a dildo before they both licked it. Before that, she had made them lick her feet. The look on their faces as they were humiliated and made to humiliate each other was priceless.
Mistress Gaia was not amused by what she had seen from her slave. She was not ok with how her slave misbehaved and she had to punish him. The mistress felt that the punishment had to be worth it and that is why she chose to use her muddy heels to punish him. He was given a choice between licking muddy boots and being trampled on the nuts using the heels and he chose to lick the mud.
Mistress Gaia wanted to keep to herself but this guy kept being a nuisance to her and she did not like it. The mistress was not going to let him keep doing that to her as she had a lot of important things to do. The mistress used her feet to punish him. And after humiliating him, she told him that was the easy part and if he was not careful, she would make it more painful.