Specific wincest fic with almost pegging

[jillybean-6939.livejournal.com]

Dean made a deal with Bella without Sam knowing about it. She wanted to peg him (she wanted him to go down on her first, but then changed her mind), Sam learned about it, stopped the whole thing before it happened and then there was wincest.  I think the fic was kinda long and probably not in livejournal (definitely not in Fanfiction.net) That's all I remember.

Any help would be reeeeally appreciated!

STORY (Leader of the Pack by astolat) FOUND BY dragynville.