I can't see why Totsuka Saika isn't here yet...
Looks great in a tennis outfit, has the mannerisms of a girl and on top of that, it seems that the male protagonist is attracted to him more than he is to the actual females of the anime.
Anime is called My Teen Romantic Comedy SNAFU
(or Yahari Ore no Seishun Love Come wa Machigatteiru. //yes it's that long))