My feet control the helpless slave's breathing

Description: This slave really thought he would deserve to breathe the same air and the same amount of air as his mistress ... i don't think so! i've locked him in the smotherbox and now i can easily smother him with my feet - and only i decide how often and how long i'll allow him to breathe ... and obviously i'll lift my feet only a tiny bit - so he can inhale my foot smell instead of nice clean air! i can also easily control how much pressure i'll apply to his mouth and nose - to make it even more painful for him! and since he keeps trying to cheat, i grab some duct tape and tape his mouth shut - now my powerful feet only need to keep his nose under control - making it even more easy for him to control him!