Sorry about the massively delayed post here. (Wasn't it supposed to be up on Thursday?) Anyway, I've got some health problems that have seriously thrown me for a loop and - well - this is a lovely distraction, but a distraction none the less. Anyway, this was a very difficult question - but I think I finally have the answer. And it is…
Kobato./xxxHolic
Yes, I know there was a little of this on the Kobato. tv series - but we could have had a lot more of it. (Ignore Kohaku in that picture. I couldn't find much with just Watanuki and Kobato.)
I don't really know what it was with these two series that I thought this would work so well. I did love the couple of little xxxHolic nods that I got in the Kobato. anime.
