It's a Spike/Xander fic. Something happens to Spike and he cuts his forehead on purpose to summon some witchy/demony god-mother type who can provide help. She arrives and says that her artist lover has just died in Australia. She's well-off and Spike and Xan stay with her at her posh sunnydale hotel until she eventually asks Spike to kill her because she, after all of these years (she's really really old) wants to die...
Um... that's kind-of all I remember now, but I feel like it's a really really good fic and any long-time Spander lover would have read it, so if this half-assed description jogs anyone's brain, please please please tell me the title/author because I'm going insane trying to think of it! Thanx in advance.