Katrin orders her slave to put off her botines, then he has to adore her feet in netstockings.
To educate him in more devotion, she has to intensifiy the action, so she steps on him, stands fullweight on his chest and he must do his job under pressure.
His face, especially his nose gets squeezed, if she steps fullweight on his face... pressing the odor with all her weight in his nose.