Also, it's nice that this series is finally getting interesting instead of just being a kind of weird fetish manga. We can clearly see a different side of her here. I don't know why she is doing the stuff she is doing, but I can tell something happened at the beach or during the trip. She is definitely acting weird after they were there, but only time will tell. The chapter 17 title is scaring me.
The chapter 17 title is called “you’re a virgin aren’t you?”
The chapter isn’t about Fumi but another girl character gets introduced and teases the MC for being a virgin but I’ll be surprised if Fumi isn’t a virgin at this point