Miho Azuki, Moritaka Mashiro's fiancee, once admits that she's a bit jealous that Mashiro seems to have a closer frequency to his partner Akito Takagi than he does with her, after they go their separate ways but get back together when they have the same idea. Takagi also reacts very negatively to any suggestions that he break up with Mashiro.
The guys even lampshaded it in the manga, saying that one of the reasons it was good to have Miyoshi around was so people wouldn't think they were gay, given all the time they spent together.
Nanamine and Kosugi have so much of this. It's sort of in the background when they were first introduced but by the end of the Nanamine arc, it's ... well, like◊ this.◊ And don't think people didn't notice that the second one looked a lot like a confession scene. Because they did.◊
In the latter panel, Kosugi looks rather like Teru Mikami from the duo's previous manga series. And surely not coincidental is that Nanamine has a resemblance to Light...