Extract Everything

I facesit my slave in pantyhose, depriving him of oxygen and giving him a boner in the process. Is he more desperate to cum or to breathe? Well, the answer remains a mystery. I give him a hand job, intending to ruin his orgasm, but only a few drops come out. His dick remains rock hard. Clearly, he hasn't been milked of every drop! I will continue to use him as human furniture and extract every bit of cum...