It was either relatively long, or I'm combining different fics.
1. There was some sort of a slave/bond/consort thing going on between Spike and Xander, that involved Xander getting sicker and sicker the further he was from Spike.
2. There was another vampire who acted as a manservant for the boys.
3. Also an underground/midnight garden? With lots of wood and carvings/paintings everywhere and a place for Xander to work on his carpentry.
4. Xander was willing to put up with a LOT from Spike in order for him to save face, but his deal breaker was spanking with a belt, because it reminded him of his father.
5. Another vampire was jealous of Xan's status and tricked him into disobeying Spike, resulting in a spanking with a belt.
6. Xander ran away despite the fact that he was going to die without Spike.
7. Spike went looking for him (to grovel and apologize abjectly), and saved him.
8. I want to say they all ended up moving to Vegas. Spike's entire court, his manservant, Xander and Giles.
9. Also, Xan was diagnosed with dyslexia and then educated properly once they figured out why he had a hard time in school. Turned out he was good with languages?
Tell me this is ringing bells for somebody, because I remember long and plotty and I've been craving some long and plotty fic lately.
FOUND! by the rockstar that is fgjkl86! Link in comments. ♥
Oh! Bonus that I've been meaning to ask! If you can't help me remember the fic above, could you maybe point me in the direction of your favorite Xander-as-caretaker for Spike? You know, like the ones where Xander ends up being Spike's second sire, only that's not a strict requirement. Just anything where Xan takes care of Spike. Money, food, a place to stay, hothotsex...whatever.