Sex, toilet humor, and profanity are instantly relatable in the human mind. Not only are they "private" subjects that you don't justtalk about with anyone, practically anyone, like Hef said, has a funny fart or sex story that many others can relate to and also find funny. The taboo and profane trigger instinctual responses from us, and people love to hear it. The challenge isn't in finding the most amazing material, it's in delivering it in a way that removes the embarrassment and allows people to laugh at the story themselves at the same time.