“BDSM, at least the sensation-heavy kind I do, is a practicum in distinguishing between good pain and bad. To an outsider, it looks absurd when someone who is getting their back savaged with a bullwhip stops the scene because they have a cramp in their foot – but the much-desired welts from the whip are a spiritual channel between loving friends, whereas the cramp is unintentional and meaningless, and is moreover a distraction from the party in the back.”