Severus + Regulus
Severus waited precisely ten seconds after Regulus left before he tilted his head back and swallowed the rest of his wine in one swift motion. Merlin help me, he thought. It was possible Regulus was only joking, but he knew better than to completely dismiss a warning like that. He'd have to speak to Draco when he was just a little older, and the thought was enough to tempt him to order a shot of firewhisky. He didn't, of course, but it was a near thing.