Dori had always been apathetic towards Bilbo, never cruel but never particularly interested either. But today he gave Bilbo a dull grin, "Come along Master Hobbit, I only bite if you're Kíli, and only then when he bites me first."
Bilbo turned to the young Dwarf in scolding shock, "You bit him?"
"That he did," Dori interrupted. "And that's the first rule of fighting, Master Baggins: you do what you must to see that you and your fellows survive. Kíli had lost his weapon and I had Fíli cornered. So the lad jumped on my back and attacked me with the only weapons he had at his disposal."
Bilbo looked horrified at the thought of putting his teeth near anything that hadn't been properly seasoned and Dori snapped, "If the difference between living and dying is a set of teeth then you better damn well bite, Master Baggins. And you never know when that will the last option you have."
Bilbo looked at the other Dwarves for confirmation and received twin nods from Fíli and Kíli before Balin interrupted, "Don't let them tease you, laddie. I've been in more battles than anyone save Master Gandalf, and I've only had to bite an enemy twice."
This was not at all comforting to Bilbo, and he turned to Gandalf, who continued puffing on his pipe with a secret smile that might've meant he'd never had to bite anyone, or it was his preferred method of attack. Though Bilbo wasn't sure which.
--Come to Morning, by (AO3)sunryder, (Bilbo/Thorin, John/Sherlock)