Ah, fabulous storytelling. I love the way you've depicted Snape - sullen, huddled, uncomfortable near the monument, resentful and yet yearning, bracing himself to be disappointed. The full-face panel is perfectly in character, and the exhaustion around his eyes betrays the background of war. I think my favorite scene, though, is the perspective from above, the way it gives precedence to the baby and the swirling snow as it slants down to Snape's unhappy glare. I can see the cheerless memories reflected in his face. The loneliness of that moment is the perfect set-up for Harry's cheeky remark, which promptly shatters the mood and bounces it into humor and sweetness. I adore the way Snape's face burns, hah! A low blow, but not so far off the mark, eh, Severus? And Harry's quite the doll, such a warm, snuggly turtleneck and pretty face.
You've colored this beautifully - it really does feel hushed and snowbound, and there's a hint of frost-bitten noses and cloudy breath. The blue-greys and whites contrast so nicely with the ruddiness of their skin and Harry's Gryffindor jumper. I also like the subtlety of Snape's frayed robes - the hole in his hood, his overall threadbare appearance. The nativity scene is smirk-worthy yet appropriate, and it's a great symbol for showing Snape mourning his past and then leaving it behind. (Not to mention defacing it with lovers' graffiti, yay!) Harry bundling him under the invisibility cloak and teasing him out of his glumness is lovely, as is the way you've warmed their skin tones, as if they're in front of a crackling fire instead of merely under the cloak together. The glow of desire, perhaps? Then the tracks of their footprints in the snow, and the sense that long after they've apparated out of earshot they'll still be trading sarcastic jibes (snark as foreplay!) allows the story to trail off into delightful anticipation.
Beautiful to look at, and it manages to be both poignant and amusing in nine short panels. Wonderful work.