That's literally the point of this chapter. They acknowledged that she gained a bit too much weight in the last chapter. So the two are exercising together to fix that.
When was the last time we saw the salaryman? Felt like the author kind of forgot the original duo. I mean, Ai-can stayed but the salaryman kind of got left behind when they started putting in more and more relationships.
I think it's the school-by-school basis. At my school, we are allowed to take off our shirts as we have our own undershirts underneath. I think it just depends on what kind of rules the school places. Some schools allow it while others don't.
Sorry, but I'm not reading any of that. I only know one thing and that you are a sniper. And that's enough for me to know what your doing. It's obvious that you uploaded this here out of spite and I hope you get bent.
Even if our main guy here stays as a creep. (In which I am not denying this, he's a creep who in the real world needs to learn some boundaries and to keep his junk in his pants.) It is still just a manga that's not hiding what it's written for and that I think we all know that's what we're here for.