Ryokan for the school trip, the night in the shared room

The night of the school trip at the inn. Due to a room assignment mix-up and the inn being fully booked, I ended up sharing a room with a male student. We couldn't switch rooms until the next morning. The line between the sliding door and the tatami mat was treated as the 'line' between us. The night was a one-time thing, and the room assignments would return to normal in the morning.