Reno has been playing too much Mario Kart 8 as of late. What do you think he does during glider journyes or at nights?
He plays video games.
Sleep is for pathetic mortals humans who only have one self and thus can't sleep while their other self goes around.
(Essentially, whenever Oner is in control, Reno is asleep or 'Trancing' as they call it as they technically don't 'sleep' in the conventional sense) (vice versa for when Reno is in control, Oner is asleep or 'Trancing')