I dont think this series is going in a "she's gonna become a freaky shimoneta-like pervert" way. it seems much more educational and stereotype breaking. we see the family life of a boy raised in a world more exposed to sexual things and we dont see them as freaky perverts but completely normal people that just have more knowledge on sex, which is a much better thing than avoiding it like the plague. as an example
the boy's family has more of a "masturbation is a completely normal thing boys and girls do, sex ed prep" outlook
the girl's mom seems to have more of a "masturbation is a dirty thing, that only perverts do" outlook.
the fact that the boy had a casual conversation with his mom about sm rope adds to that.(not just the rope, but that he's having this conversation with a girl, his mom, rather than his dad, a male(who are always seen as more sexual))
My guess is that this series is trying to teach its readers that sex and the many flavors of kinks and fetishes are normal things that people have, as we see the female mc realize that., while a budding romance slowly brews, which is neat-o