Cas sits on the edge of the bed, like he had when he'd just met Dean and woken him in the middle of the night to fetch Sam. He watches the rise and fall of Dean's side, follows the slope of his back all the way up to his neck, the short buzz of his hair. The way the fabric of his shirt bunched at his waist, how he placed his legs. The sound of his breath.

"I suppose so."

It had never been about him before. Only when it had been about him did Castiel start to screw up. Before, when everything had been about Dean, things were hard but things were right.

Castiel thinks he understands now. 'To love is to put it before yourself,' one of his brothers had attempted to explain to him, when he was still young and trying to grasp God's order to love the humans. Obey God, love Man. That had been the mandate.

Now, finally, Castiel thinks he might understand.