Buffy under spell - takes off w/ Spike

I cannot remember what season it takes place, but it starts off w/ Spike finding Buffy in his crypt painting her nails black. She takes on his personality, smokes, and they run off partying together. At the end she comes back to herself. I don't know if I am describing the story well, but this is what I remember. Thanks so much!

I think that's Love Like Fire by Addie Logan: http://spikeluver.com/SpuffyRealm/viewstory.php?sid=25255&warning=NC-17

That's it - thank you so much!