"My poor Sora." Riku leaned over and kissed the side of his head, to make it feel better.
"I will not go off at night," Riku agreed. The Prince couldn't really expect him to just sit around their room all day, waiting to see if he's show up. "I'll most certainly be back, always, before the sun falls. And I'll stop letting the time run away from me, and try to be back for dinner." That sounded reasonable. Back in time for dinner, and then his time was strictly the Prince's.
That only left the time between lessons and dinner, but if he grabbed his lunch to go, it was about 6 or so hours.