"Oi!" Sirius faked an offended expression, too used to this kind of treatment to really mean it. And anyway the big grin splashed over the little girls face didn't really make her any good at insults. He poked her gently in the side, worming his fingers under her ribs to tickle her. "I'm not old, you cheeky little git."
Then skinny arms were around his neck and a kiss was pressed to his cheek. Sirius wound his own arm around her waist, keeping her steady while returning the hug. Sirius had always been good with kids - Lily said it was because he'd never mentally matured past ten himself. But he loved Dora and Harry fiercely, and he enjoyed their company. It was a relief at home, when everything else was falling apart under the weight or war and death suspicion, to spend some time with his cousin and her chatty, excitable little girl.
"I can play with you," he agreed. Regulus had the mini-version or himself and his brother, after all. "Although it's a bit of a surprise for me too. I didn't expect to see you here!" Sirius eased himself to his feet, keeping his arm around Dora so he scooped her up with him, her small body curled on his hip. He nodded at the comment about Alice, although something lurched uncomfortably in his stomach.
"She hasn't been very well," he explained. "We need to be nice to her." Then he quickly cast around for a change of subject, the little girl still balanced on his hip. "Is it my turn to hide now?"