All 4 of the marauders were nervous walking towards defence against the dark arts that morning, in fact the entire class seemed nervous, including Lily Evans, which was a strange sight for the boys, particularly James. I suppose you couldn't blame them for being nervous, I mean they were about to share their deepest, darkest fears with the entire class, and had no way out of it, and it's not like they could lie. This scared Sirius more than he cared to admit because what would they do when they found out Sirius' biggest fear was his mother? Would they call home? And that struck fear in him, if they called home he wasn't sure he'd be able to come back to Hogwarts next year.
Remus could see it in Sirius' eyes, Remus' biggest fear was the full moon, which would spark confusion, but only four people in the room would understand, but Sirius' fear would gain everybody's attention, and he didn't know how he was supposed to handle that.
James and Lily's fears were almost the same thing, both about their parents dying, though one involved a girl spitting at her and calling her a 'freak' whilst the other was just his parents. Nobody really knew what Peter's biggest fear was, but figured it'd be something similar to James' and all this did was scare Sirius more, because his fear would strike the attention of everyone at Hogwarts as soon as word got around.
He couldn't bear this thought and that made his breathing quicken, Remus saw this though, and placed his hand on Sirius' knee sending a reassuring smile his way. This slightly calmed the boy, but his hands were still shaking.
Slowly the names of people to cast the spell against a boggart were decreasing, Sirius getting more worried, others looking more relieved, nothing as striking as Sirius' fear came up, most people's being things such as failure or spiders, nothing like Sirius'
His thoughts wandered off, what would Regulus think? He didn't really care what his parents would think because either way they hated him. Either way he'd receive a million beatings in a few weeks when students had to return home for the summer, and Sirius wasn't looking forward to this one bit, his attention was brought back to the class when he heard the name 'Potter' being called, and watched as his friend walked up to the giant chest, it revealing his parents dead on the floor, and hearing a strong 'Riddikulus!' come from the boy, the professor sending congratulations his way. After Potter there were four names left to be called, and his fear only increased as an 'Evans!' could be heard.
He watched as the red head walked to the front, taking a deep breath as an image similar to James' appeared once the chest had been opened, the same defense charm being cast, the next name was called "Pettigrew!" and watched as his friend walked to the front, the boy's image taking the shape of failure, failed exams, being called a failure, a stuttery "riddikulus" escaping the boy's mouth. There were only two names left to be called, his and the boy sat beside him, his breathing quickened and his heart began racing, he sent an attempt of a reassuring smile towards Remus.
"Lupin!" was the next to be called, Sirius couldn't bring himself to look at the front this time, he knew how much Remus feared himself, and that hurt him, and with the racing thoughts already clouding his head he just couldn't bring himself to do it, he could hardly breathe by the time the seat next to him had Remus in it again, his being the last name to be called, he shakily walked towards the front, bringing his wand up as the screaming woman emerged from the cupboard, pointing a wand at him, the class was filled with a deadly silence by now, hexes and curses being sent his way, that's when he realized he couldn't do this, he was frozen in fear and couldn't bring himself to cast the spell. He didn't give up trying, he kept attempting to bring his wand up, but he just couldn't, no matter how many times he tried. An "avada ked-" could be heard before he heard a familiar voice shout "riddikulus" unfreezing the boy, that voice belonged to Remus, of course. That's when it hit him, in that moment everything just became too much so he just ran out of the classroom, and up to the 6th year Gryffindor dorms.
He just dropped to his knees, sobs escaping his mouth, he was struggling to breathe, and could hardly hear when two boys came rushing in after him, dropping by him, "hey, hey, just breathe, deep breaths come on, in, out, in, out" he eventually managed to calm his breathing collapsing into two pairs of arms belonging to Remus & James.
It'd been a few hours since the boggart at this point, Sirius was laying in Remus' lap "you okay Siri?" he lightly shrugged, "what happened in there, it really happened didn't it?" Sirius nodded lightly "Reg pushed me out of the way before the spell could hit me" Remus just hugged him tighter, lightly pressing a kiss to his forehead.
I might rewrite this, I don't really like the last part of it but I wanted to upload something
