The slave is on the sofa and Katrin takes place on his soft belly.
She uses his face as footstool, while he has to change her the shoes and boots.
It's not easy for him to put on her the boots with the other is pressing hard on his face.
Katrin is a little sadistic and places the heels of her boots so that it's very uncomfortable and painful for him.
Then he has to move to the ground, Katrin uses him as a stair-step and sits down again.
Now from a higher place she can act better with her boots on his face, means more and harder facesqueeze under the soles.