Sirius and Regulus
Sirius had no doubt why Regulus had left the reception, and really the scene he'd made wasn't even out of character for his brother either. And maybe in the past Sirius would have stayed and enjoyed the rest of the night, while perhaps simply ignore Scorpius, but that his brother had made a point to suggest he leave as well Sirius didn't feel quite right staying.
"So." He said when he'd caught up to his brother in the halls. "That was quite an exit you made back there." He grinned. "Though if you'd really wanted to make a point there could have been some hexes or something added to it as well." Though in a room full of Weasleys that was probably not the best idea in the world, Sirius could admit. "It's really too bad there wasn't an ice sculpture to blow up or something." He said wistfully as he finished.