Because mistress Celestia's boots are brown, it is easy to the dirt on them. Her slave missed the dirt on the shoes and assumed they were clean. But the mistress knew they were not and that they had not been cleaned. She wanted her slave to always be careful so she wore them and used them to punish him. She trampled him using the boots and she also removed them to make him smell her sweaty socks as punishment. She made him do this while she was reading a book.