1) I genuinely can't remember a manga ever even acknowledging the existence of dandruff before
2) to say nothing of using dandruff as the motivation to start a shower sex scene
3) but really this ecchi-ass manga doesn't exactly need even flimsy excuses to start any sex scene in the first place???
4) actually now that I think about it the combination of 1), 2), and 3) is pretty much the most Takahiro thing ever