There are Hard Limits that are respected and which are not to be transgressed or even approached. These are to be determined and agreed upon and most often done prior to submission to service. There should also be a safe word that is established to prevent any actions or continued action that is unbearable. To inflict severe pain that is not mutually agreed upon is not the proper actions of a Dom/Master and if this be His intent I would question His motives, intentions and true belief in the lifestyle.