Mahiro's Difficult Class

Mahiro's Difficult Class (まひろとかこくなじゅきょう, Mahiro To Kakoku Na Jukyou) is Chapter 22 of Onimai: I'm Now Your Sister!. It was originally published on Pixiv on November 24, 2018.

Summary
Mahiro endures her first gym class as a girl.

Plot
Mahiro sighs while putting on her school uniform, noting that it is another depressing day. Mihari notes Mahiro saying that, but points out that she dressed herself without her prodding. Mahiro is shocked by this herself, but claims that she just didn't want to have to do it in a rush if she slept in. Mihari asks Mahiro to be honest with herself, and gives Mahiro her bag which she packed with her books and things. Mahiro notes that it seems like a lot of stuff. Mihari pushes Mahiro towards the door, telling her that her ride is here and that it's time to go. This so called "ride" turns out to be Momiji and Kaede who are going to walk with Mahiro to school. Mahiro immediately cheers up and tells Mihari that she's off.

As they walk to school, Mahiro complains that she is so tired, wondering what kind of person gets up early just to walk a mile carrying heavy bags. She remarks that Mihari should just get her driver's license and drive her, an idea which Momiji calls ridiculous. Mahiro notes that she feels like she is about to see if she can learn in her sleep, and wonders what first period is today.

After hearing chatter in the classroom, Mahiro becomes shocked that it is gym class, realizing that her bag was so heavy because there were gym clothes packed in it. Mahiro calls it the terror inflicted upon all students and truly the dark side of public education.

Without even thinking about it, Mahiro begins unbuttoning her blouse. Momiji asks her what she is doing, and Mahiro realizes that the boys can now see her bra. Mahiro covers back up in a panic, realizing that she went along with the boys without thinking. Mahiro chucks it up to still being half asleep, with Momiji telling her that she needs to pull herself together. Satsuki and Minori tell the boys that there is nothing to see and that they are the worst for peeping. They boys claim that they didn't see anything, and Mahiro asks for their forgiveness. She starts to wonder if she should do something to make it up to them, but Momiji tells her that they should go. Mahiro realizes in horror that they are about to head into the girl's locker room.

All the girls start undressing, and Mahiro gets nervous wondering what a pickle she's gotten into. She notes that there are half-naked schoolgirls everywhere, and that they are the last thing that she should be looking at. She decides to focus on Momiji to calm herself down. Seeing the flat chested Momiji and Asahi calms her down, with Mahiro comparing it to the "desolate beauty of the great plains". Mahiro remarks that she's glad that at leats she doesn't have to be concerned with Asahi either. Asahi is confused by that statement while Momiji is surprised by it.

Mahiro realizes that she hasn't heard a peep from Miyo, having figured that this would be the highlight of her day. Mahiro sees Miyo changing alone in a corner, and goes to ask her why she's doing that. Miyo becomes surprised and turns around, revealing a very developed female figure that Mahiro was not expecting. Miyo turns back around embarrassed and tells Mahiro not to stare at her like that, Mahiro also turns around and apologizes. Miyo remarks that she stares out too much in gym clothes and that it is embarrassing, but one condolence is being able to wear tracksuits in the winter. Mahiro realizes that having big boobs can be tough too, and thinks to herself how boobs are surprisingly complex.

At the outdoor track, the gym teacher Rin tells the class to group up in pairs to stretch. Mahiro and Miyo group up and begin with Miyo saying that she hates this part. Mahiro apologizes and notes how she can see how this would be embarrassing. Meanwhile, Momiji tells Asahi that she'll definitely beat her today, and Asahi remarks that that is exactly what she wants to hear. Mahiro notes that the too are very fired up, and Miyo tells Mahiro that the two are both athletic types.

Rin tells them to line up, and Mahiro asks what they are doing. Miyo tells her that they are running laps all month, something that Mahiro feels dread about doing. Rin tells the class that today they will be running ten laps and recording a baseline, saying that the first group should get ready. Mahiro shudders and thinks to herself that she can't do this and that she is feeling sick already. Miyo asks Mahiro if she's okay, saying that she doesn't look so good. Mahiro says that she has a bit of a stomach ache.

Miyo raises her hand and whispers something in Rin's ear. Afterwards, Rin tells Mahiro that she can just watch for today, much to Mahiro's delight. Mahiro sits on the ground and thinks that she is not sure what happened, but is so relived. She is glad that she is supposed to be sickly. She adds that she is feeling a little better since she's sitting out, but that she should at least cheer Miyo on. This does not help though, as Miyo gets embarrassed from Mahiro staring at her.

Asahi eventually comes in first place, and Momiji comments how fast she is. Asahi takes in the praise, and Mahiro tells everyone that it was a good hustle. Mahiro thanks Miyo for her help, and Miyo says that it is no problem. She whispers into Mahiro's ear and asks her is she has what she needs and that she just needs to ask if she needs to borrow "one". Mahiro is confused, then realizes in horror that Miyo thought that Mahiro had started her period and told Rin about it.

While eating dinner with Mihari, Mahiro tells her about it and adds that now she can't bring herself to correct Miyo. Mihari is amused by the story.

At the same time, Asahi, who overheard everything, asks Momiji what Mahiro and Miyo were talking about, wanting to know. Momiji just cringes at Asahi's innocence.

Characters

 * Mahiro Oyama
 * Mihari Oyama
 * Kaede Hozuki
 * Momiji Hozuki
 * Asahi Ōka
 * Miyo Murosaki
 * Aoi Tachikawa
 * Nodoka Fushimi
 * Satsuki Tadaka
 * Minori Shiina
 * Nemu Fujimi
 * Yuta Sakurada
 * Minato Senkawa
 * Rin Minakata

Trivia

 * First appearances of Minato Senkawa and Rin Minakata.