Oh, so lovely! That was a wonderful read. I loved your Draco (especially in the 'drenched ferret' version at the beginning, and his astonished happiness at encountering Snape, and his determination at seeing his desire for Snape fulfilled.
And an absolutely gorgeous hermit!Snape, with his bit and sarcasm intact, but lonely and deeply attracted to Draco, and prepared to take control during sex :). Very, very hot too, with the two complimenting each other perfectly in personality and desire.
I also loved the idea of Minerva's 'dower cottage' (and Minerva's and Narcissa's roles in the background of this story immensely.