Excellent primer video on the meat-and-potatoes aspects. No snark or sneers or judgments. Granted, they steered clear of the sexual-fetish plane that we live on, but even other videos like this dismiss tickling as "childish" or otherwise trivial. Like others who commented, I don't agree with everything, especially the reasons why tickees smile/laugh/seem to want more. Although I do believe that the physical stimuli are an evolutionary defense mechanism, I can't believe the convoluted explanation that ticklees express pleasure merely to ensure that we learn to defend ourselves. I believe in evolution, but that seems too circuitous a route to a strong defense.