Wow, yeah, we all called it -- a major theme is the emotional separation walls that people feel due to social gender filters. Noel calling the protag "Kei-chan" again in the same chapter Eito started calling them "Uesugi" again. Notice Eito asked despite knowing full well what his friend was doing: that was resentment towards Noel if I ever saw it. I have to wonder what in the world a seemingly sweet girl like Noel could have ever done to earn it. My guess is that he's gay (notice he averts his eyes in chapter 1 when "BL" is brought up) was lowkey attracted to Uesugi and resented the latter's crush on her. Recent events have taken his best friend even further away from him.
And oh boy... if "Kei-chan" wasn't thrilled about being a girl before, they're REALLY about to not like it. We're in for a ride -- this might not be the first time the author details a girl's first period with an almost TMI-level level of description. (I say "almost" because said manga was lowkey meant to be sex-ed in the first place)
I believe you're thinking of
Naisho no Tsubomi, which was definitely meant to be a sex-ed manga for young girls, but she went into a fair bit of detail about Yuuko's period in
Mizuiro Jidai (aka
Aqua Age ) as well, so this next chapter might be uncomfortable for some of the guys. (And if this series ever gets animated I expect a bunch of guys to totally lose their minds over the episode dealing with it, like they did over Mahiro getting a period in
Onimai.)
And yeah, weakness, stomach cramps, highly emotional to the point that they don't even understand why, Uesugi's
definitely about to learn about the lovely hormonal rollercoaster that becoming a girl has put him on. I really hope Noel, his sister, mother or one of the other girls from his class happen by to help out.
Nothing says that Keisuke had to transform into a body that was at the START of its menstrual cycle. Also, pheromones will actually influence a woman's monthly cycle and can make it shift around--studies have shown that women who live together will tend to shift their cycles based on each others' menstrual cycles, so Keisuke's sister and mother could be influencing her body already.
That brings up something I've thought about with genderbender manga/anime:
What determines how the menstrual cycle plays out in the newly minted girl's body? There's a couple of possibilities I've thought of, it could start the day they change. Although
where does it start? With ovulation? (Two weeks to period.) With the day after the menstrual bleeding would have ended? (Three weeks.) Hell,
with the period? (That'd be one hell of a shock, kind of surprised the goddess didn't do that to him.) It could be in the midst of where it would be if they'd been born a girl. (The change is magic, so why not?) Or like you suggested, maybe being around other girls will trigger it.
If you want to really hurt your brain, try to figure out how Ranma from
Ranma ½'s period would work. Does it track with a monthly cycle regardless of when he changes? Only tracks with time spent in a female body? Something else entirely? It's where I first thought of the question and that one still hurts my brain if I think about it too much.
Almost certainly, since it's combined with muscle weakness and emotional instability. Breaking down crying over stuff is
very common early on, it's hard to learn how to manage it. That's why teenage girls are so renowned for being moody as hell.
What does this "88" even mean in your context. Am I clueless or something?
It's a hate symbol, code for
Heil Hitler, because H is the eighth letter of the alphabet. You'll also see it combined with 14 for "14 words" which you can look up yourself, because I'm not quoting the fourteen word sentence it refers to. I was behind a car with a 1488 bumper sticker on it once and it really pissed me off. Most people aren't that openly racist, though, thankfully. (And to be clear, when they're combined it's unambiguously a hate symbol, not say someone that graduated high school in 1988.)