Devero's fingers clamp tight on Koumyou's as he fights to keep the turmoil under control. Had it been just Koumyou who reacted he might have even been able to force himself to calm down, at least physically.

But Yondu acknowledging as well... kind of undoes him.

He hides his face in his pillow as panic rears up and seizes him by the throat. "Sorry, I'm sorry," he says, still gasping around the stranglehold that she yet has on his psyche. "Being stupid. Should have just said it, sorry--"

Yes, Devero, you're reacting like this just because you didn't want to say an impolite word. That is definitely the issue here.