Harry Potter Headcannons

Sirius black

Sirius Black who shakes when the sorting hat is placed on his head, and asks for anything but Slytherin, and he doesn't know, but it was never even a consideration.
Eleven year old Sirius who gets bad dreams about his parents, and the sorting, and his family, and his little brother, and dark magic, and crawls into the dorm bed next to his own, because James doesn't mind and rolls to the edge of the bed to make room.
Twelve year old Sirius Black who finds Remus Lupin crying in the library and sneaks him into the kitchens instead of going to class, because he knows talking to James makes him feel better than crying alone, and he wants to be somebody's James.
Sirius Black who takes care of Remus Lupin, because he knows what it's like not to have anybody to take care of you.
Thirteen year old Sirius who's boggart is his own parents, with words like Mugglelover and Bloodtraitor heavy on their tongues, their wands at the ready.
Thirteen year old Sirius who's Head of House gets a visit from his defense teacher because of his disturbing boggart.
Sirius Black who starts having weekly teas with McGonagall and has a positive, loving, close, authority figure for the first time in his life. McGonnagal understanding Sirius and listening to him, and teaching him, because a boy who grew up in the toxicity of the Black house had a lot to unlearn about the world.
Fourteen year old Sirius who starts spending more and more time with the Potters' until he comes to spend a week and the guest room has become his room and it has posters on the wall and it's newly painted with matching sheets and he thanks Ms. Potter over and over, because he doesn't have to keep his door shut here to keep anyone away here and he feels safe for the first time in a longtime.
Fifteen year old Sirius who still flinches the tiniest bit when people shout and has hands that shake when someone lectures him too harshly.
Sirius Black who still gets the nightmares every now and then, and wakes James up and sits at the end of his bed and talks to him until they both fall asleep again.
Sixteen year old Sirius who gets a common bug and has to spend his break in bed, teasing Ms. Potter that all this pampering is why James turned out so spoiled. Ms. Potter's heart breaking because she had only made him soup and brought him extra blankets, and this kind of love was something foreign to him.
Sirius Black who wears James clothes as much as James wears his, because they've been living together in and out of school for a majority of their lives, and they're not really sure who the original owner of the Weird Sisters shirt was, but now it's whoever's hiding it in their closet at the moment.
Seventeen year old Sirius who graduates, and his parents aren't in the crowd, of course, but the Potters are and McGonnagall is, and James is next to him, and Lily has gotten him a leather jacket like the Muggles wear, and Remus is crying, and Pete is talking about the future like it's covered in gold.