This was all the encouragement that Sirius needed. Nobody had ever been that enthusiastic about his flying before, because he was competent enough for a boy his age, but that wasn't saying much, not when others in the family were accomplished Quidditch players and the like. Even in his lessons here on the station, Arcturus was reserved in his praise.
He flew down closer to Philip again, and said, 'I can do better than that! Let me show you!.' And then he was away, demonstrating various turns and rolls in the air, vertical climbs and drops, and all the other little tricks and skills he'd learnt. He took it slowly, as he was supposed to, but to someone who had never seen flying before, it might have been impressive. It didn't seem quite enough for Sirius, though, and he decided to take the broom up to its top speed. This took a little time, and he had to fly higher still, and go out beyond the gardens and into the fields beyond, but soon enough he was racing along at forty miles an hour, making wide turns and zooming past Philip, way up above.
Speed demonstration done, he slowed a little – perhaps not as much as he should have – and went into some fancy spins and spirals again. This was showing off a little, and he knew it, but he couldn't resist, because when was he ever going to get this change again? It all went splendidly, until the increased speed meant that he mistimed a rolling maneuver, so that when he finished it, he wasn't upright on the broom, but hanging upside down. There was a way to right himself from this sort of mistake, but instead, Sirius panicked. His hands slipped, and he dangled down from the broom by his feet, and then they slipped too, and boy and broom went tumbling to the ground.
Had Sirius been a year or two younger, his natural magic might have protected him from the fall. Had he been a little older, he might have had the presence of mind to avoid the accident. As it was, he hit the ground hard, and there was a sickening crack as he landed with his left arm under him.
For a long moment, he was absolutely motionless, there on the ground. Then he sat up, bolt upright, and when he looked at his arm, now clearly twisted at an unnatural angle even with the sleeve of his robe draped over it, Sirius couldn't help it. He began to wail, fat tears running down his cheeks. It hurt! It hurt so much!