Now that Transfer-kun is making their move, what will Fukami do? Probably just go "Oh" which will make our ML a little angry and he'll probably leave like that, so that Fukami can then go after him WAIT NO BECAUSE THAT WOULD BE LIKE EVERY OTHER TRANSFER PLOT.
I don't think Fukami can go too. He has his sister. Even tho she's getting marry, she's his family, and they take care for each other. Or well, maybe that could happen, knowing that his sister has someone there for her and her son, and also that Fukami has Kaji. But I'm not so sure about both of them transferring
The uke is sneaky and makes the seme believe someone wrote dirty words on his body, and the seme (younger, glasses) sees the words when the uke gets wet from the rain.
Probably this
http://www.mangago.me/read-manga/junai_drop_out/
The neighbor also went down the old "Communication? Saying things out loud? What is that?" route. He's an idiot. I hope our MC boy here can actually see that, because there's no way neighbor dude can accuse ML of stealing his past crush or something. "Your boyfriend used to be a slut." "I know." End of the arc.
P.S.-And please, there's nothing wrong with being promiscuous, as long as you're doing it with consent and self-care and you don't go around messing with couples on purpose.