I always see Japan written as secretly (or not so secretly) being a yaoi fan, and it's always bugged me because he's a dude after all. So I would like to see him as a fan of bara and getting hot under the collar when some of the manlier men get into each other's personal space. Fantasizing is very welcome. It would be especially cool if a stereotypical yaoi-like scene happened in front of him and his imagination somehow turned it into bara. Humor please.

Bonus: He secretly gets a thrill out of Greece and Turkey fighting over him for this reason.
Double bonus: He experiences some confusion over his regard for Hungary and her confrontational relationship with Prussia, since she's the manliest character in the series and all.
Triple bonus: His bara fantasies of the others have them just as OOC as if they were overdone seme/uke stereotypes.