I know it's not a lot to go on, but I do remember that Willow and her unethical magic usage was a central theme to the story.
On another note (or possibly a related one, I can't even remember any more), there was a story where Xander and Spike live together in like an abandoned warehouse (or a mansion), and that's also the same place that Spike holds his court, only in a different part of the building, and Xander's not really allowed there without supervision. Spike has three main leutenants that keep things in check and a pretty big court. He goes missing and Xander has Angel come and keep a lid on things until Spike comes back.
And then there was one where Xander gets beat up by his parents (again) and Spike takes him in and makes him move into Spike's home (which I think is Angel's mansion, appropriated from him). Spike is apparently pretty well off, so he can afford things like a new bed and wardrobe for Xander and to take him out and stuff. Willow and Tara bring over a liniment that's supposed to help ease the aching and the paining and Spike doesn't think it's going to work fast enough to he bites into his own thumb and mixes his blood with Xander's V8 juice.
I remember really random things, I know. But I hope these details ring some bells out there because these stories stuck with me and I'd like to read them again. I'm also pretty sure they're all 'older' stories.
Any help is appreciated!
EDIT: FOUND! by the the helpful wrtr_aka_wmgrg and silkensky. Links are in the comments!