I finished volume 3 of https://learnnatively.com/book/8a5621742a/ and immediately went for volume 4 since the (non-romance) plot started moving.
And got really surprised. 
instead of plot, first chapter almost immediately goes into a (somewhat) spicy scene. Most of the surprise comes from the fact that the romance part was kinda stuck in a will-they-won’t-they that seemed like it would go on forever. But I guess it won’t (that’s also why I am not putting all that behind spoiler tags; I almost dropped the series thinking nothing will ever happen).
I found funny how the author seems extremely averse to any explicit description of what is going on, using wording like this instead:
柔らかい場所を何度も撫でられる感覚に力が奪われていく。
（あ、う……っ）
Ah yes, a “soft place”, must be her earlobes. It does feel good indeed.
