The main credo of those into BDSM or rough sex play, in which the goal is to inflict pain to their partner. A mantra, to insure that one can have extreme limits, but that there are limits not to be crossed.
Part of the Leather Code, which mainly asserts the right for consenting adults, to engage in sex, that has the infliction of pain as its main goal.
It further stipulates, that pain should not result in actual harm to those involved, whether mental or physical in scope.
The basic premise, includes that any damage done, must be able to heal, and to not have long lasting repercussions, but again, based on individual biases.