I am almost positive it can be found on Twisting the Hellmouth, and is about Xander sorta seducing Angelus away from releasing Acaltha, complete with leather pants and self-oral (too cool!) But I cannot find it, nor remember title or author. I know Spike winds up in the mix later, and Xander being able to bring back souls?
I plan to remember the link this time promise! Thank you in advance for any help