Bokutachi wa Benkyou ga Dekinai: Nagisa ni Usemono Arite Senjin wa Enzen to [X] Suru
The episode adapts chapters 48 and 49, which follow Yuiga and Asumi going on a fake date, and Yuiga encountering his teacher Mafuyu Kirisu after she accidentally loses her swimsuit top. (Source: MAL News)