FOUND! Bottom!Sam and angry top!Dean
Looking for a fic I read recently, I believe it had a few chapters. Dean was angry with Sam about Ruby and the demon blood, even though Sam wasn't drinking it anymore. Sam basically consents to Dean punishing him for it non-sexually, but then it becomes sexual when Dean realizes Sam is aroused. Dean puts in place some system of saying the word "over" means this thing is done between the two of them. Near the end Dean slaps Sam (I think in the bunker), they have rough sex and Dean says "over". Pretty sure it ends happily. Any help is much appreciated!