Bokutachi wa Benkyou ga Dekinai S02E06 - Wherefore Might They Fathom the Aspirations of the Immediate X

When Mafuyu can't use the bathtub in her apartment, she goes to a neighborhood bathhouse. On the way, she encounters Asumi and Nariyuki, and ends up in the sauna with Asumi. It's so hot that the two get punchy.