Totally understand you, but if you’re talking about Koyama and Hidaka, they are actually 16-year-old high schoolers who are at an age where plenty of horny high schoolers lose their virginity and by Japanese law, can consent to sex
I think they are referring to the last chapter and how Ayato got excited to see "another Ueda" in tomoharu's little brother, who is in middle school. But I think it was just a joke, Ayato is obviously being paired with Takeuchi
Tomoharu's little bro is 15 tho lol (not to justify ayato of course, it was just to clarify)
It's a no on the 12yr olds fucking.