This is absolutely mystifying. Perhaps we are bearing witness to a rare ritual of exchange with few parallels to human culture, or perhaps I'm stuck in xenothropology mode from -con and reading too much into it.
Panel 2: Chen: Dis ish Mishter Veggie? I ged id! Reimu: Wha! That's a tasty looking Mister Cabbage
Panel 3: Chen: Afterward, I can ead id together wish Ran shama. So happy!...... yu? Reimu: Chen!! Won't you share a bit of that Mister Veggie with Reimu?!! SFX: Grumble grumble (I think)
Panel 4: Chen: That Big Sis is also hungry...
Panel 5: Chen: I Get it! But just take a little! Reimu: Thank you! Then it's time to eat, easy!