My bet is that she spilled beer, and had to undress both of them so they wouldn't catch a cold.wholesome ending to cringe moment, but funny how that girl decided to confide in sensei with MC right behind her. Coulda been a bit more grateful, but she did seem to internally celebrate the small victory.
meanwhile, at home: more shenanigans! We know it's a bait, but we can safely say now that Hiro has slept with half the cast in 6 chapters. 9/10 MC, keep it up! Wait what were the tissues for?