As much as I hate explaining a joke, much less taking more than a paragraph to do so, I will because this is one of those "it was funny when I was drawing it" comics.
The idea is that Leko is apparently watching some sappy romance anime. (It's actually Ouran High School Host Club, which is about as far from a serious romance story as an anime can get, but someone just glancing at your screen while you watch it wouldn't know that. Especially when you've got headphones on and they can't hear it. The abundance of pink and flowers makes it look unbelievably girly.)
Thus, Leko felt the need to switch to something more characteristic of him to be seen watching (giant awesome robots, a la Gurren Lagann) as Tailii does a double take.
TL;DR Leko pretends he's not watching a romance anime.
The idea is that Leko is apparently watching some sappy romance anime. (It's actually Ouran High School Host Club, which is about as far from a serious romance story as an anime can get, but someone just glancing at your screen while you watch it wouldn't know that. Especially when you've got headphones on and they can't hear it. The abundance of pink and flowers makes it look unbelievably girly.)
Thus, Leko felt the need to switch to something more characteristic of him to be seen watching (giant awesome robots, a la Gurren Lagann) as Tailii does a double take.
TL;DR Leko pretends he's not watching a romance anime.