I really hate to leave these but I've been wracking my brain and bookmarks for a month and still haven't found it.
I'm looking for a story. I remember that something happened to Xander early on while Buffy was visiting her dad. Angel did something to save him and later had to claim him before Xander died . Buffy came back and Xander told her about his sex or die situation with Angel. I had just gotten to the part where Xander had realized that he had new gifts due to the claiming.