A little more on the comedic, a little less on the realistic side like her usual stories.
Well, what do you expect of a guy trapped between an uke and a seme, I mean it's clear who he ends up with as soon as you see the cover picture.
The manga is not bad for what it is though. Jin looks young just because he's short. His face doesn't scream "young" as much as many many other mangakas would have it.
He's 15, with Seigo being 20. It's not really the end of the world! I agree though that the story moves very fast and has not much substance. It's hard to follow the characters and their actions. Despite there being three men who turn gay all of a sudden, the topic of homosexuality doesn't come up at all, all you get is a "but I'm a guy" and that's that.
The characters are not clearly defined uke or seme, they're something in between (not when it comes to sex but more the way they look or act!)
Nevertheless, I liked Jin as a character. He's quite fun because he is so persistant, he just goes in and takes what he wants and stands up to other no problem, even though he's young and short!
It's an age gap story. Problems like being treated like a kid, looked at as an equal, sex are being handled here and the manga does that alright.
The charm of this manga lies in the atypical characters! It's not the usual cookie-cutter roles where you look at the first page and you know exactly who is a seme and who'll be his uke and it's just clear like that. If you need a break from the 0815 type of characters, or you just enjoy persistant (much) younger semes who are the driving force, and clueless ukes, then give this a read.
That being said, I don't think this manga to be anything special either. There are better age gap or young seme stories out there, and Fujiyama Hyota sensei also has much much better works released. It's a light one-time read.