I couldn't find a Hobbit or LOTR-specific fic finding community so I hope you guys can help.
It's set in Beorn's house. The Company decide Bilbo needs to learn to use his sword and Bilbo is reluctant. It turns out that all the Shirefolk are taught the Breathing and the Ways when they are wee little babies. As a gentlehobbit, Bilbo is only expert at unarmed combat, but other families have their own Tool styles. Belladonna was called the Mistress of Feathers. Bilbo happily takes on all comers in a glorious brawl, and Dwalin is in his element. Kili crawls out of the scrum requesting permission to go back to the Shire and recruit more hobbits.
I remember all this, but I don't have a title, an author, a bookmark or a favorite and I am disgusted by myself. I read it on AO3, and distinctly remember commenting and kudos-ing, but I can't find it in my email or AO3 history at all.
ETA: Found! Para Bellum, link in comments. Thank you
jelaza!
@mods: I picked LOTR as the fandom as there is no Hobbit option...