It's a bit unfortunate that the amusing "teach Peri how to eat" scene can never be canon, since Peridot can't shapeshift- she wouldn't be able to make a digestive system. If it was, Amethyst would have known that fact before Too Short to Ride.
That’s an interesting observation! The implications of which change a lot of their dynamic. One possibility (given Peri’s disgusted face at Amethyst’s instructions) could be that Peridot’s refusal could be chalked up to not wanting to shape shift. It’s not unheard of for gems to reject food, Pearl would have been on Peridot’s side should that have come to pass. It’s still a scene worth exploring though. In Log Date, Amethyst is comfortable with confronting Peridot but Too Short to Ride Amethyst has also confronted herself on several occasions.
If that’s the case saving the revelation for TSTR was great timing, though should the Peri eating scene have occurred, there is a way it could’ve been spun to keep the truth hidden a while longer, and Peridot’s aversion to shapeshifting a digestive system would have been chalked up as foreshadowing.
I mean just look at this face.