The slave kneels in front of us and stares at our dirty shoes. We tease him a little and tell him what is most likely stuck to the soles of our shoes. He will now lick that off and eat it in front of us! We evaluate his performance and appearance during as he goes about his task. Both turn out badly for him and that makes it even more humiliating for him than it already is. We don't care about that though. The main thing is that he eats everything and we have fun!