It's simple. You start off with three words like "Once upon a" then the next poster will post something like "time there was" and another poster will put "a burgundy hippopotamus" and so on...
I have NEVER met Cheyenne Jackson. I have never hung out with him in his dressing room, he did not tweet me, he never bought me a beverage, and he mostly certainly didn't tickle me. . .that is all.