Little summary: while Terumi is out, Kaoruko wanders into Terumi's room, starts to wonder if all nights she spent alone were so lonely, lays onto the bed smells Terumi's scent and she almost touches herself.
Terumi's friend suggests that he should quit the experiment with Kaoruko. And jokingly adds that if he wants to start an incestous relatioship now, that's another matter.
Terumi starts to think that Kaoruko has changed recently. He does not understand the reason, but finally starts to wonder what she gains from this whole Genji experiment. He then grabs his phone, because he just wants to listen her voice just a bit. Then quesions himself about what he is thinking there.
Chapters 246 and 247 happen at the same time parallel to each other.