[Ooh, not a pokemon after all then. Seeing Rin's put-out expression at the increasingly common nickname she's been saddled with, Koo realizes that's who Sans is talking about. He chirps happily, which gets him a shush from Rin to keep it down, though he doesn't look bothered. Yes, that's his trainer!

Starting to get a little huffy between the two of them and her own fatigue, Rin straightens back up to make the bed proper, grabbing the blankets (which knocks Koo off balance into a tumble that lands him on a pillow) and waving them out to drape over the mattress.]

I'm not some kid that needs to be tucked in and read a bedtime story. Do whatever you'd like; I can take it just fine from here.