Castiel had stopped having nightmares by the 12th night. His sins still plagued his thoughts during the day but he had solace at night. He had Dean. And so on the 13th morning, with Dean Winchester's arms wrapped firmly around him, Castiel whispered, "Does this mean you'll stop holding me at night?" He was afraid, he did not want to lose Dean, no matter how irrational that want was. Humans are irrational, and he was a human now. His question caused a low chuckle to rise from the green eyed man beside him. His hand cupped Castiel's cheek and he whispered, "I wouldn't dream of it," before leaning in to place a sweet, chaste kiss on the fallen angel's lips.
Castiel decided that he did not need the missing piece of himself, as he had Dean, and all the Grace in heaven was nothing compared to Dean Winchester.