ok so this is a headcanon
what if remus listens to classical music? not just because it’s a “nerdy” thing to do, but because it’s truly soothing to him. being able to appreciate something that’s so intricate and layered like a classical piece speaks to his humanity – so on the days leading to the full moon when his mind is the most troubled, listening to some of his mother’s old muggle vinyls becomes a habit. when he’s focusing on the different sounds of the different instruments, he’s reminded of the work that goes into putting all of those things together and he’s able to focus on the different emotions they evoke.
while sirius is in azkaban, he plays one or two of those old classical pieces in his head because he’s memorised them over the years. the dementors can’t suck the music from him because it’s not happy memories that it brings – the music reminds him of remus’s pain and the fear that he associated to the impending transformation, and sirius is able to keep playing the music in his head and to cling to it to keep himself sane.
so years later, when they’re both living in grimmauld place, they manage to fix an old record player one day and then remus pulls out the vinyl with that one piece. sirius’s first reaction to the music is to cringe because now on top of everything it also brings back locked-in-an-azkaban-cell feelings but then remus just pulls him by the hand and they sort of slow dance to it in the middle of the sitting room??? and everything is okay with classical music in the background??