WTF is a sedoretu?

sconesforjustice: bemusedlybespectacled: I really fucking love sedoretu fic, but I don’t see a lot of it. Part of it’s probably that it inherently involves poly-shipping and that’s not something everyone likes to write, part of it’s probably that it’s hard for all the characters to fit in neatly to the ship, but part of it…