Katrin orders her slave to remove her the boots. He needs to much time for doing this, so she's angry and the beginning of her trample-action is harsh.
She steps on his body and marches with the next step on his face.
The moaning under her is musig in her ears and motivates to increase the action.
She walks and stomps in place, then she steps again on her favorite place....
His face and throat!
Her 150 lbs are doing a perfect job in face-destruction.