YES!!! thank you for asking, this was so much fun to think about at work <3
Before they start dating Remus regularly gives Sirius song suggestions, they’re rarely love songs but they’re always related to Sirius somehow. There might be a specific line that describes how Remus feels about him or a guitar rift that has the same vibrant energy. It’s never meant as a love confession, more as a relief- a brief moment where Remus can let his love spill over without worrying about the outcome. (he’ll also annotate books and give them to him)
The flat they move into after school is small. It’s one or two bedrooms and worn down, but in a way that makes it feel warm and lived in. Their bookshelves are overflowing with old books and there’s rarely a moment where music isn’t playing. Their fridge is covered in photos. Sea shells and other knick knacks cover the window sills. They have rows of teas for guests to choose from and are always stocked on snacks. Their flat just feels like a home and people are always coming and going from it.
Remus says I love you first. They're standing in the streets of London one night and the snow is gently falling, getting caught in Sirius's hair as he laughs over a story he tells. The Christmas lights are glowing against his face and Remus can't stop the words from coming.
They love finding spaces outside of their home that are theirs. They have a bench at the nearby park where they sit and watch the ducks with a coffee and pastry. They have a corner store down the block where they’ll buy cigarettes and sweets. There’s a diner they visit when they’re both hungover and a booth where they always sit- Remus always gets an English breakfast and Sirius always orders a stack of American pancakes (but only ever gets through a quarter of it before he starts feeling ill and eats off Remus’s plate instead). They also both get black coffee (this is the only time either of them ever drink black coffee).
When Sirius is going through a bad period (whether that’s a day, week, or month) Remus will be extra aware of asking before he does anything for the other even if he knows it’ll help. Especially if it involves touching him. (Ex: Can I change your socks? Can we sit in the tub and wash your hair? Can I hold you?)
The first time Sirius receives a letter from Hope and Lyall addressed specifically to him he spends hours crying and for the rest of the week wells up anytime he looks at it. Remus mentions this to his mum and Hope takes special effort to write to Sirius at least once a month (he writes back to every letter using his best paper and seals them with a wax press he bought specifically for her)
They both read tons after they graduate! They’ll spend afternoons laying together in bed or in the park reading. They’ll recommend books to each other and watch the other read their favourite parts to see the other’s reactions. Breakfast is often spent talking about whatever they’re reading. Sirius uses whatever is close by as a book mark (old receipts, scrap paper, old post it notes) while Remus uses a polaroid photo of Sirius.
Remus loves kissing along Sirius’s wrists, his neck, his inner thighs, and his ankles, always slow and breathless, and Sirius loves leaving big, exaggerated kisses on Remus’s cheek.
Deciding whether or not they want to have kids takes years. Remus would love to have them but he loves Sirius more and understands if his boyfriend doesn’t want to have them. For Sirius it’s much more complicated. There’s days he wants nothing more. There’s weeks where he can’t trust himself. His opinion changes often, shaped by his persistent fear that he’ll turn out like his own parents. When he finally does decide he wants them, he announces it randomly one morning when they’re in the kitchen making tea. Remus pulls Sirius into the tightest hug and whispers how proud he is of him. (they make amazing parents)
Sorry it's a little long but I hope you like!!