Fair bit to talk about with this one. First and foremost, the scene was actually inspired by a Harry Potter fanfic I read a couple years ago. Deathly Hallows was coming out soon, so I was getting all [figuratively] horny for the wizarding world again and decided what the hell, and read this fic called The Seventh Horcrux, a fan version of the final book, basically. I surprisingly wound up enjoying it quite a bit. It was a bit heavy on the shipping at times, but there were a couple others parts that had me sobbing like a little girl.
But there's this part at Christmas where he and Ginny just basically spent the evening snuggled up on an easychair in a corner of the room together. I mean, there was a LITTLE more to it than that-- it'd be a boring chapter otherwise, but that's the only part relevant to this here deviation I posted. That's as far as the similarity goes, but that mental picture of them enjoying their Christmas stuck.
As for what we have here, well, it's in the title, isn't it? Voldemort's been worm food (though the worms find him none too palatable) for a good six months or so, and these two nice kids are free to spend their first Christmas together.
I figure they were curled up on the couch together for awhile, and Harry reaches into his pocket saying "Hey, what's this in HERE!" pulls out the present, and holds it way up where Ginny can't reach, and she has to damn near climb over him to get it, and Harry can smirk and say "What'll you give me for it?"
Oh, and the "what will you give me for it?" is supposed to cute and playful. So, if you were thinking of something DIRTY, shame on you. You've ruined Christmas. I hope you're satisfied.