This old guy thought his age was a ticket to do whatever he wanted. It worked for him but not with these mistresses. They never cared who someone was. As long as he or she pissed them, he or she had to get what was due to them. When they assessed this guy's mistakes, he was made to lick their boots until they were clean then he had his mistakes forgiven.
This slave did not want to do what he was supposed to do. He felt like he was being made to do things he did not like and he sort of rebelled. But the mistress was not going to let him get away with it and that is why she invited her friend and both of them humiliated him with their boots. He had to lick their dirty boots clean.