Fresh slaves have to be sitten in by Mistress Cathys royal booty. The first sit is really important and most of the slaves change their mind once the princess puts her bbw ass on their faces. To avoid any escape the mistress uses her personal invention: The smother chair. Her slave is fixed in a box with his hands cuffed, unable to move, and his face looks out. So she can start sitting on his face and is assured that he wont try to get away and disturb her while relaxing and turning his face into her personal cushion.
