1. Cas and Dean get interrupted just as they're about to have sexpollen/cursed!sex. I remember that they were about to do it on the table, but Sam managed to break the curse or kill the witch or something. Dean freaks out. Also, I think I remember the author mentioning that she thought sexpollen/cursed!sex should be marked as dub/noncon.
2. Dean thinks Cas and Sam are together, or at least are attracted to each other? Really vague, I know, but it had something about Dean thinking the both of them geek out at the same stuff and they had a lot in common. I think it started off with him happy that they were becoming friends (I'm not sure) and ended with him telling Cas that he was happy they were together and he was trying to be a good brother and that Cas chose the better man/Winchester.
Sorry, I just got struck by a sudden need to read these two, and I can't remember where I read them.