That was funny and cute, thanks for sharing.

Spoilers from those 2 chapters: Basically a trap who sucks at doing manly things and who is always teased by girls for that, wants to become more manly. So he gets an injection that will let him change his life and become his ideal self (he thinks this means more manly.) Of course he turns into a girl.

In chapter 2 the class leader says she was always looking at him and that she wishes he had been a girl, kisses him without knowing he has changed (she seems to be a lesbian). Then she ets infected and turns into a guy too.