I've played a few games with intentional joking. For anything short of having the whole game built around such humor, nothing short of a clear mod and or "optional" method for such a thing comes to mind. Such changes, even if minor, very dramatically disrupt the immersive feeling for the game.
At most, I would have to imagine it like Fallout: NV's model. At the start of the game there is what is in effect a comic perk. The game bluntly says it will add in some whacky things sprinkled into the game, and it is meant to be silly. A similar thing maybe could be added here, in that a whacky mode could be unlocked, if (big if) enough interest was found in it.