We Never Learn: Bokuben season 2 episode 6
Episode title: 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.
