Castiel's jaw clenches a bit, but after a moment or two of silent deliberation, he nods.

Yes, he understands. Pushing to three is not something he wants to do. He needs this, needs Sam to lay into him and put him back in place, punish him for all he's done.

However, he might consider pushing to 2... later. For now, he opens his mouth, throat dry. He hates seeing Sam like this. Oh, he hates pushing Sam to this, too. And yet he still does it. Castiel will make amends for this, later.

"Yes. I understand."