Training His Breath Holding By Facesitting

Ive put on a big stopwatch on the computer screen - and ordered the slave to be my office chair. And Ill stop the time he can hold his breath! And Ill not make it effortless for him - Ive put on a very hard jeans that will surely flatten his nose. I think a minute shouldnt be a problem... or will it be? Well, well see - but Ill make sure the loser suffers under my arse - hell be without mercy strangled and feel my full weight on his face! He doesnt truly help himself by fighting that much - he just wastes so much oxygen... he should just keep peaceful... guess Ill need to train him longer! And I truly dont like to be disturbed by his shrieking - so I put on headphones and embark some music - then strangle him again and the timer starts once again! Unluckily, I can still feel him fighting... so I guess next time Ive to tie him so he cant stir and then put on the headphones!