Cas had never been the most affectionate angel in the garrison, but missing his marbles made him lose all his inhibitions. He would show up naked, covered in bees, dressed in nothing but a trench coat, or worst of all: decorating Dean with kisses and stickers.
Dean wasn't dealing with new crazy Cas on the best of days, but this was the one thing he didn't mind. He knew somewhere in that messed up feather brain it was about making up for his mistakes, so he allowed it, as long as no one mentioned it.
Sam noticed how his brother had softened- after all, he was the one to point out that Dean would never wear a pink band-aid; but he took it as a good sign that someone might be breaking through that barrier Dean had built so high.
The stickers were easy enough to hide under his many layers of clothes, and the ones that ended up in any place he couldn't cover with another plaid shirt, well, they just "fell off" after a few minutes. The kisses weren't so bad, the only awkwardness was how everyone else in the room would stop and watch as the ritual occurred; first a chaste kiss and then the gold star. Meg learned to bite her tongue after the third time when Dean decided he had heard enough and tossed salted holy water in her face. Cas had to break it up by changing the subject to which board game they were going to play, or which pet they should adopt. His head hilt and puppy dog eyes didn't hurt either.
The kisses were actually the hunter's favourite part. Something about it reminded him of the secret that he and Cas had shared- the subtle touches and moments of holding a look a little too long. Before the world almost ended, again, before a new breed of monster can set a fire under that pot.
Cas had trouble explaining himself in human words, in concepts so small to him. He preferred to act as he felt than put his actions into words. There was a myth among humans he had been told of once; in which a child born with red blotches or marks upon their skin were referred to as Angel Kissed. He liked that idea; to believe that a child's soul had been blessed, carried in the hands of his brothers and a kiss laid upon that baby's brow. There was a kind of magic in it. There was also a kind of truth.
While these children simply happened to be born with a birthmark and not with the help of a warrior of God, the kiss of an angel could be powerful. Powerful enough to mark a human soul.
His lips would seal the kiss of love and protection, would show his desire to be forgiven; they would mark Dean as his own. Even if he could never find it in himself to fight again he would know he had shown the love he needed the hunter to see.