Facesitting Oxygen Test

How long do you think this loser can hold out? Mistress Jane and Queen Hanna give the slave an oxygen test. For this the mistresses take turns sitting down with their awesome butts on his face and take away his air. With their butts hard on his face he cant take even a single breath. With a stopwatch they time the slave to see how long he can bear being under them. 5 seconds and and .