His face falls, and almost instantly the color drains from his cheeks as Katsuki's dart around and see pint glasses of hot, mulled wine...hot toddies, and even a few people just straight up pouring rum into their glasses of eggnog. Sure there's cocoa and hot tea around, and Katsuki had some spiced cider himself, but how can he be sure the kid didn't get into something she shouldn't? They have sticky fingers, and they're overly curious, too... He's also pretty sure, when he was that age, he totally nabbed one of his dad's left bottles of beer to 'try'. It was vile, and he didn't take more than a gulp before spitting it out (all over the floor, no less), but still. The shit being served here is hidden with all sorts of other flavors and spices.

"O-Oi, oi!!" he is now reaching for the kid, plunking her down right in his lap and feeling her forehead, her neck, and maybe tilting her head to see how focused her eyes are. "What was the last thing you drank? Where's your cup, hah? Did it taste sour? Bitter?"