Based off the following prompt from a friend: How Sirius Black first felt when he turned into his Animagus.

Not beta-ed. I don't own Harry Potter. The capitalization is funky and Sirius is angsty. You've been warned.

James is first. One night, after months of studying and another of failed attempts, he attempts the transformation and succeeds. He becomes a stag. There are two and a half weeks left until the next full moon and this means they're almost there. As they'd already christened Remus Moony, when James is back to normal after a round of wrestling with his friends to get used to his new form, Sirius claps him on the back and says "Congrats, Prongs. Always figured I'd be first but I guess I can't fault ya."

James attempts the change a few more times that night and manages all but twice. Sirius and Peter both fail, though Sirius is sure he comes as close as he possibly can without making the switch. Remus, who usually half-watches them as he does research for whatever homework assignment the four of them are shirking off in their attempts to become Animagi, watches James with rapt attention, smiling a huge smile each time he manages to change. Sirius turns to face away from where he can see Remus and James.

When they leave the classroom they use for their practice sessions later that night, Sirius fills himself with new determination. That night while he lies in bed he can't stop thinking about Remus' huge smiles or the hug he'd given James after he'd first managed to change back. Remus may have thought he'd been sly with how he'd wiped the small tears from his eyes, but Sirius hadn't missed it.

Sirius had honestly thought he'd be the first to master the transformation. He was the star of their transfiguration class- even Professor McGonagall couldn't deny it. He had been so sure. And to be honest, he had wanted badly to be the first. He had wanted so badly to prove to Remus how much it didn't matter to him that he was a werewolf, to prove how much he wanted to help. James making the transformation first had cheapened that; at least Sirius thought it did.

Sirius shakes himself out of his thoughts. They're not good thoughts to have about his best friends. At least, he tells himself, if James had to be first, then he can certainly manage before Peter. That's something Sirius can depend on.

Peter's next. He becomes a rat a nine days after James becomes a stag and a week and a day before the full moon. James dances around with him in their animal forms, Remus gives him that same smile he gave James, and Sirius christens him Wormtail.

Sirius cries in bed that night.

Suddenly there's two days before the full moon. James and Peter, though not quite masters of the Animagus transformation yet, hadn't stopped practicing and were planning on spending the night with Remus in the Shrieking Shack. They laugh raucously during dinner and Sirius does his best to laugh along with them. James can't stop cracking thinly veiled jokes about werewolves and the shrieking shack and for once it's Sirius, not Remus, worrying about them being overheard.

They go to their classroom after dinner but after James and Peter transform back and forth a few times, James pulls out- from Merlin knows where- a pack of butterbeers. He toasts to his transformation, to Peter's transformation, to Remus' good health, and to Sirius' future transformation. The last is said with a wink and a nasty little smirk that Sirius loves when James directs it at Snivellus but hates when it's directed at him. He knows James doesn't mean anything but fun by it but he still hates it. He says cheers with his friends and drinks the butterbeer but the whole time he wishes they would stop and practice longer.

Remus, James, and Peter spend the night before the full moon working on whatever homework it was that Flitwick had assigned that day. They sit in the common room and Sirius tries to sit with them and write his essay for Flitwick. When he finishes- way before his friends with the bare minimum length and a shitty structure- he tells his friends he's headed to the kitchens for a snack and goes to their classroom. He's not sure how long he practices but eventually he gives up. When he gets back to the dorm, his friends are already in bed. He gets under the duvet of his own bed, closes the curtains, and sleeps as soon as his head touches the pillow.

Sirius saw his friends off the night of the full moon the same way he usually did with Remus. He swore he saw Remus smile as they walked away from the Gryffindor common room- a real genuine smile and not the fake ones he usually gives James or Sirius when they crack a joke about Remus' time of the month on the night of a full moon. He watches from the portrait hole until he sees them round a corner, James reaching into his bag to pull out his cloak as they do so.

He doesn't stay in the Gryffindor common room for long. He tries to. He thinks of James jokingly telling him to be a good boy and behave while they're gone and of Remus much more seriously telling him that he should work on his homework and to stay out of trouble if he can manage. He figures that ditching the common room after he's made his way through some of his Arithmancy problem sets in favor of a little practice doesn't really defy either of their orders, as it's not yet curfew and he doesn't plan on getting caught anyway. He doesn't need James' cloak to get around the school undetected.

He goes to the classroom where they practice their transformations and he practices. He tries and he tries again and again. And then he tries more. He thinks of every book and journal and article he'd read in the months before he even attempted the transformation. His nearly photographic memory serves him well and he channels all of the knowledge he has on the subject as he tries the transformation again and again.

When that method doesn't work as well as he hoped, he changes methods. He thinks of an ancient journal that had told him to tap into his animal side. He'd had to owl his cousin Andy to get it from the Black family library, which hadn't exactly been easy for her while she was already on her way out of the family. He hopes the trouble she had gone to wasn't in vain as he reaches into his magical core and pulls out his animalistic side.

It doesn't work for the longest time. He'd thought pulling for his animalistic side was a bunch of bull but he thinks he's closer than he was before. This is certainly more work and he's working harder than he ever has at this transformation. It's well past midnight and probably only an hour or so from dawn when he thinks about giving up. He's sweaty and disheveled and he's sure his hair is appalling. He's almost sure it's time to give up.

Then suddenly he's sure he feels it- the shimmering feeling James and Peter have both described as coming right before the transformation. He figures he'll try it one last time, to see if by some magic (ha) it actually works.

It does.

Suddenly Sirius is staring at the top of the desk in front of him. He's changed into something else. An overwhelming sense of happiness fills him. It flees quickly for a sense of satisfaction and then that's gone and replaced with a sense of urgency. It's a whole new experience this four-legged body but he's done it and he needs to get to his friends- to Remus. He could finally prove to him that he meant it when he said he was doing this for Remus because he had done it for Remus.

He jumps onto the desk to look into the window. He's a giant, shaggy black dog, a fitting choice he thinks. Another look, this time through the window and his eye catches on the Whomping Willow and, behind it, the Shrieking Shack. He jumps off the desk and runs through the door. He rushes past Mrs. Norris and ignores her small screech.

I'm coming, he thinks. I'm coming, Remus.