Caniformes by give_it_a_little_nudge

Caniformes - give_it_a_little_nudge

Wow, took me a month to read this super long fic, the longest in the supernatural fandom on AO3. This epic covers only 7 months in time excluding the 'Then' sequences and the epilogue. A well written fic with excellent world building, some scenes are not for the squeamish.

Source: http://archiveofourown.org/works/10686864