WARNING: Bathroom humor/language!
Spoiler:
.....In other words, what is it that inspires you to laugh? It varies from person to person, but luckily God, in his infinite wisdom, gave us a great starter kit. To put it quite simply, the penis is funny on its own. The thing looks like a long-lost Marx brother and yet it is the instrument of reproduction. And let's fess up to the truth here: When it takes control of the brain—which is most of the time—it actually acts like a Marx brother. And that's when the fun explodes, so to speak. Then there is the fart. You have to be brain-dead not to think a fart is funny. Sure, laughing at a run-of-the-mill bodily function is juvenile, but a brilliantly lit one—one that sparkles and flashes like a Fourth of July fireworks display—is a joy to behold and puts a smile on any young man's face.
..........— Lewis Black (1948.-.), American stand-up comedian, author, playwright, actor. Me of Little Faith (2008).