Big spoon/little spoon: Because of their size difference, Thorin is almost always the big spoon - when they are spooning, I mean. Often they just sleep in a tangled mess of limbs and blankets and fur. Bilbo likes to sleep on the top of Thorin, using the dwarf as some kind of personal pillow. (First it isn’t actually comfortable because Thorin is pretty bulky, but after years of living and eating like a hobbit, Thorin manages to grow a little tummy and Bilbo loves to use it to rest his head on.)
Favorite non-sexual activity: Bickering, though often it tends to lead to sexual activities… They both like having longs walks, smoking and music. Often when the night grows darker, they sit down in their living room, take their pipes out and just sing together. But they actually sing quite a lot together - Bilbo loves to make up little songs when he’s preparing food, walking, or having a bath and Thorin often joins him with his deeper and lower voice.
Who uses all the hot water: They both love long, hot baths, but Bilbo baths more often than Thorin. You wouldn’t think so, but even though Thorin is all ~royal and majestic~, it’s always a fight to get Thorin to bathtub - and when you finally get the dwarf to bath, it’s another fight to get him out before his skin is all wrinkled up.
Most trivial thing they fight over: Well, they are constantly bickering to each other and they can start a fight over the most ridiculous things - but that’s just how they love affection to each other. Though there are some things Bilbo is ready to raise a hell for: (1) dogs do not belong to bed,(2) dogs do not come inside with dirty paws and (3) dogs do not eat from the table (and (4) Thorin isn’t allowed to point out that Bilbo himself breaks this third rule all the time).
Who does most of the cleaning: Thorin, because Bilbo does most of the cooking and Thorin doesn’t want to feel completely useless. (Bilbo just laughs at this because “we both know I only married you for your pretty face” and then Bilbo gets a slap on his ass because rude.)
What has a season pass on their dvr/who controls the netflix queue: Well, they don’t actually have TV in the Shire.. But if they did Bilbo would of course control what they were watching because Bilbo is the master of the Bag End, after all.
Who calls up the super/landlord when the heat’s not working: If they need someone’s help with the house, Bilbo is usually the one to go out and get it because he knows neighbors better than Thorin. Though lately Bilbo has realised that Thorin is much more up to date with latest gossip than Bilbo is - Thorin is in terrifyingly good terms with Gamgees.
Who steals the blankets: Thorin, because he’s surprisingly sensitive to cold. He’d like to sleep with dozen layers of clothes on, but Bilbo doesn’t approve of this - so Thorin just wraps himself in blankets and of course there’s one certain hobbit making sure Thorin doesn’t get cold.
Who leaves their stuff around: They both do, but Bilbo is worse at this than Thorin is. Bilbo can be really absent-minded and he gets very easily distracted - so he often just drops books and papers and what-ever-he’s-carrying-at-the-moment to the floor or nearest table, or on the couch. Thorin’s problem lies in clothes - when he gets inside he just strips while walking from the door to kitchen and casually just throws his clothes around.
Who remembers to buy the milk: Neither of them, they are not good with this kind of mundane stuff. Often they are already sitting on the table when they realise they are missing something vital - and it’s Thorin who runs then to the market place or to Gamgees and asks for bottle of milk. Or honey. Or eggs. Or slice of ham. Or bread. Or butter.
Who remembers anniversaries: Thorin. Like mentioned, Bilbo can be really absent-minded and he’s bad at remembering dates and other trivial things like that. Thorin isn’t actually better than Bilbo with remembering things - he’s just too soppy. Thorin remembers the day he first time entered the Bag End, the day they first time smiled to each other, the day they first time slept in a same bed, the first time they kissed, the first time they had sex.. And of course he remembers their wedding day as well.