What I love about this interaction is that thus far in the episode, Day has come off as a rather stern boyfriend who is annoyed and frustrated with Itt, who comes across as emotionally manipulative and whiney. But this minute long exchange between Day and Gear changes everything. Suddenly we see that Day is not, in fact, annoyed with Itt to the extent that he appears to be. He loves how much Itt needs him, depends upon him. That Itt will whine and complain about wanting cake, but Day has fully trained him to not go get it himself. I think he gets off on Itt’s whining, because it’s proof that Itt has fully accepted Day’s complete control over him.
I also enjoy the peek we get into Day’s mind when he says that he’ll do anything to make Itt his and his alone. There’s a flash of complete insanity in his eyes. And Gear sees it. After that exchange, Gear goes from being on Day’s side to being entirely on Itt’s side. Because Itt is only the way he is thanks to how Day has groomed him(excellent translation, btw).
All of this sets the stage for the flashbacks we see in the following episodes, of Day being physically abusive in order to force Itt to never leave his side. Day doesn’t want Itt to have anyone else in his life aside from him. He’ll tolerate Itt spending time with their mutual friends, but he’d never let Itt spend time with anyone one on one, except perhaps Night and Gear, and that’s only because they live together, and Itt isn’t allowed to leave the house while Day is gone.
Agh this show is so good I wish it had a larger fanbase.