Nya's little sister is very popular

I'm sorry for the vulgar topic, but this time, Yanineko's embarrassing "toilet habits" in the train station toilets and his apartment room cause a huge commotion involving those around him. Meanwhile, at school, a prince-like girl who secretly has a crush on Imoko gives her a present. But the contents of the present are once again related to toilets... Furthermore, thanks to a "common sense alteration app" that Yanineko has acquired, he transforms into an extreme anti-smoker!? By the way, there is absolutely no change in his sense of cleanliness. They should have altered that too.