The official series has specific pairings. Doujinshi allows for the exploration of alternative pairings or outcomes that the original author did not pursue. This might involve the rejected partners finding solace in one another, or scenarios where the swapped couples decide to permanently switch, accepting their new lives—a diverging path from the often tragic or ambiguous endings of official episodes.
"This isn't hentai. This is a tragedy disguised as hentai." fuufu koukan: modorenai yoru doujinshi
If you were to create a story based on this title, consider: The official series has specific pairings