As far as I understand, the talking member is responsible for the humorous component of the game. If we approach it from the point of view of realism, then most likely this is a split personality caused by painful shock and toxins when the wasp stung the MC at the beginning of the game. But considering how the main character’s dick has grown, this is an insignificant price to pay and I’m sure many would happily agree to it.
Well, the dialogues in the game are quite funny, humorous, of course not a masterpiece, but they never bothered me.