For example, in episode one, the hand scene a bit after the 5 minutes mark... to me (and not only to me, but to many other guys as well), that looked quite gay. It just looks really homosexual to a guy.
Perhaps to the author and to girls in general it seems normal. It is the kind of scene you'd see in shoujo and josei manga a lot, after all. But to me, even if it isn't actually homo, it does look that way, hence why the "undertones" as slimed put it. There were other scenes as well, but that first one was already one of the most ambiguous in the whole series.
I know full well the author did not mean for any homosexuality to be in this, but the execution doesn't exactly make them look as manly men doing straight things... though only every now and then.
With that out of the way, I'll say it again: this show is really good and is worth checking out. And it's not gay.