Today I'll smother the slave with a twist. I'm going to sit down on his face with my full weight - but I won't get up - he'll have to lift me up when he wants to breathe! Obviously, this is getting harder and harder the less oxygen he has in his lungs. After a few minutes he's struggling immensely and can barely lift me a couple of millimeters with shaking muscles - but of course, the fear of being fatally smothered by my ass is a good motivation :-D