Well, this best friend in question is usually a bit better for drinking and sex, but hey, the fun doesn't just stop there. And anyway, he's completely ace at Christmas Decorating. Or the exact opposite of that, he tends to forget which one.
It shouldn't make a huge difference.
"So. I think the lights go first," he says, once he's here, taken a proper amount of greeting kisses, gotten his coat off and had a look around the place. John's not super sure what Q's done with it, but he's a bit uncomfortable. "On the tree."