Rereading this now and I feel like people are being too hard on the rape. Like if you don't like rape and don't read rape stories then that's fine, but I like the rape in this story as a plot element.
***Spoilers***
It's not that Wakamiya doesn't want to have sex, it's strongly established that he desperately wants to have sex, it's that he's terrified of accepting his gayness because of his father being staunchly opposed to gays. He calls Kirishima a rapist to push him away and keep him from chasing after him. Kirishima rapes the girl because he is in denial of being gay himself as well (like he is so desperate to prove that he isn't as quickly as possible, that he tries to have sex with her in spite of her not wanting to), and rapes Wakamiya because it just got to the point where his feelings of desire (and possessiveness with Wakamiya saying he would have sex with anyone) overwhelmed him and he couldn't stop himself. It's used to portray how overwhelmed the characters feel and how heavy the conflict is. It has plot relevance and they make all instances of rape in this sad and visceral unlike many other yaois that romanticize it. I really liked the use of rape in this manga.