Caesar:
I think most writers do at least subconsciously put part of themselves in all their characters, darkness is part of our collective subconscious and I think all people technically have it in them to be good or evil depending on the circumstances of their lives which is why many people who are the nicest people in the world can write about such sordid characters and subjects.
Well, "in all of their characters" strikes me as overstating the point here--generally, I'd venture that writers tend to put significant aspects of themselves into their protagonists and possibly one or two other major characters. However, they certainly might also model some characters, strongly or loosely, on other people from their real-life existence.
Does a protagonist-vs.-antagonist conflict represent a "Good vs. Evil" struggle between aspects of the author's own persona? It obviously could, but it doesn't necessarily have to--some villains are created purely to create an opposing 'counterpoint' to the protagonist rather than to reflect the writer's 'dark side,' I'm figuring.
Of course in a spanking-oriented story, even one featuring truly punitive chastisement(s), there may not be a "hero vs. villain" confrontation in the classic sense--both spanker(s) and spankee(s) could approve of the corporal correction administered, albeit often rather grudgingly in the case of the spankee(s), thus making it a consensual, cooperative situation--at least once the offense(s) involved have been committed and discovered.
Then again, perhaps if the spanking implement is considered "heroic" and the targeted bare behind "villainous"...

--C.K.