The ambivalence of tickling, a delight that can quickly become excruciating, would seem particularly well suited to describe the concept of pleasure-in-pain that so fascinated thinkers from Plato, Nietzsche, Freud etc. They agree that tickling serves as an alternate way of thinking about pleasure,  as titillation and excitation. Nietzsche put it, “What is the best life? To be tickled to death.”

This episode is also available as a blog post: http://martinifisher.com/2017/04/23/titillatio-a-brief-mythology-ancient-history-and-philosophy-of-tickling/