Looking for a fic
The story had Watanuki going along as the school archery team was going to a three day tournament. Of course he was forced to share a single room with Doumeki. But the big detail i remember is Doumeki's back was deeply bruised because someone's bowstring broke but he still won the tournament.
I don't remember the title or author but i do remember reading it in lj - here or the author's page.