Laughing at his lover's antics - no doubt made funnier by the alcohol he'd consumed - Gaius went willingly into Sirius' lap, wrapping arms around him and kissing him back enthusiastically. Then he pulled back, chuckling as he rubbed his nose against Sirius'. "You know, I'm not the only one with tall, dark-haired, attractive brothers, you know. And Regulus doesn't have a jealous werewolf or a big, strong Auror to get in the way." He meant it as a joke, of course, and turned to wink at Harry.