Amanda & Sirius
He had originally intended to avoid the bonfire like the plague. Sirius had been removed from the human population for six months, locked in the most horrid prison that any sick mind could have thought up, and he had assumed that throwing himself into a large group of people would be the exact opposite of what he had needed. He went from losing his best friends and being betrayed by one to sitting in solitude for what felt like ages, and although Sirius was more than thrilled to be out he was still concerned that perhaps he was a little more unstable than he himself was aware of. It was a scary place to be in, mentally; broken enough to be unsteady, but self-aware enough to know that he didn't know just how unsteady he was.
But the sound was too much. He had eaten as soon as he had gotten to the camp, limiting himself to two portions because he hadn't managed to eat in over four days and he could feel himself starving, like he usually was. He didn't want to make himself sick, and he also didn't want to show up and end up eating the entire stockpile of food the community managed to save, especially since he hadn't managed to make himself useful just yet. After that the noise and laughter had called to him, and Sirius realized how much he wanted - no, how much he ached to be around other people. It was conflicting. He missed speaking to another human being, but he was afraid of being overwhelmed all at once.
He was also afraid of how much they knew about him, and what they did and didn't believe.
That fear came secondary to his innate desperation to be around another living being, so Sirius found himself slowly approaching, looking from strange face to strange face until he saw someone sitting off to the side. She was distanced from the rest of the group by just enough to make him comfortable, and with a deep breath Sirius approached her, still managing to turn on that charming smile despite the fact that it felt completely foreign to his face now.
"Mind if I join you?" It was the first time he had spoken aloud since he arrived and his voice sounded strange to him. Raspier, perhaps from a lack of use. It was the best type of culture shock, though. Who could complain about being pulled out of the worst prison in wizarding history and dropped into a paradise?