Literally no idea. I've had multiple occasions when it went well past what I thought were the limits of my tolerance, where I thought I was going to lose my mind, but I mean I can't imagine it was longer than ten minutes? Probably more like five minutes? Nobody was timing it so I have no way of knowing but I mean ten seconds of nonstop tickling is so intense, I can't imagine going past ten minutes. Plus the people tickling me would surely have an attack of compassion -- or at least get bored or lose interest -- by then, right?