Classic culture clash in the comments, though I think that's good - it shows how manga can bring very different perspectives together. In the west, 15 year old couples getting freaky is very, VERY standard, so western readers see no issue. I know that for instance in India (just off the friends I have from there) that there is far less boy-girl intimacy until way later in life than in the west, so it makes sense how this can come off weird. The Japanese are a very.. repressed culture, so we see them getting really really freaky when they can. Seen best in their media, but also how big things like JAV are, as I know porn stars have idol status there. Same for a bunch of grown men being very into idols. So its very logical that teen romance manga can carry a sexual element like this. It'd be a bit more off if they were 12-13, but 15 is that transition period between middle school and highschool, when students start to develop an extremely strong sense of independence and become rebellious, it's the exact time for stuff like this to come out of the woodwork.
I've had similar experiences as the two in the chapter did in my own teenhood too and found it extremely relatable. The awkwardness was captured just perfectly. It's EXACTLY how this stuff goes the first few times. Imho, it's an amazing chapter.
