A Room Of One's Own by NorthernSparrow
https://archiveofourown.org/works/1417834?view_full_work=true#main
Dean/Castiel

Excellent story with an interesting view on how Dean and Castiel go from friends to lovers with Dean in denial most of the way. Castiel’s interest in learning how to behave in a more human fashion in order to please Dean after walking in on him masturbating is funny as hell. It all turns on Dean finally having a room of his own and some privacy and goes downhill from there depending on your view. The wing scene is erotic the first time and hot as hell the second time. However there is a surprising depth to Dean that shows when he finally confronts Castiel on just what is happening. Dean is determined to fix what he didn’t realize was broken. He also finally realizes just how important Castiel is to him and tries to give back some of that support and devotion. The dialogue between them as they argue about fetishes and just what is a turn on is hilarious especially since Dean is trying to hide all this from Sam. The funny part is Sam who is aware of what is happening and has just been waiting for Dean to say something. He has has even nudged things along a little.

How (thanks to Gabriel) Dean and Castiel (accidentally) Raise Each Other (and Sam)

How (thanks to Gabriel) Dean & Castiel (accidentally) Raise Each Other (and Sam) by Vera_Dragonmuse

http://archiveofourown.org/works/540915/chapters/961503

Great story with an interesting story line. What if Castiel became involved years earlier with the Winchesters. As Gabriel lay dying he could see what was coming and decided on a desperate gamble. Using his remaining grace he goes back to a time when he spoke to Castiel and named him the angel of Thursday. He asks him to be the angel of Dean Winchester as well as Thursday and surprised Castiel agrees. Gabriel and Castiel watch the future Gabriel die. Castiel does not think further of that until Dean's mother calls his name for a blessing on her child. Castiel is involved in a war but remembers and checks on the infant. Later he feels the pain and fear of the mother and child and appears in time to see what happens. He decides the best way to be there for Dean is to grow with him. He finds a vessel that is dying the same one that he would later use and begins to appear to first just Dean, then Sammy and later in their teens he decides it is time for their father and Bobby to know of him. The story changes enough but remains true to the Supernatural story line. The growth of the relationship between Dean and Castiel is built wonderfully. The relationship between Sam and Gabriel is surprising and at one point hot as hell. John Winchester is alive and still a suspicious bastard. Bobby agrees with a lot of Castiel decisions to give the boys a better life.