Stranded by Michele. Rated R.
A short, strange, sexy circa-season-4 tale. Xander. Spike. Angel. Deserted island. When vampires start wanting to kiss him, Xander is sure he's either dreaming, or things are getting pretty damn weird. Except things are *always* weird around Xander, aren't they? This story always made me want to shake Michele gently, ply her with choccies, and get her to write the *sequel*, dagnabbit! (Thanks to Minitrog for reminding me of it.)
Last Men Standing by Maayan and Kita. Rated NC-17.
AU future, post Season 5. The final battle with Glory cost more lives than just Buffy's, in this world. Years later, two vampires spin painful circles around each other, bound by love and hate and barbed wire, until the final survivor walks back into their lives, and there's a chance for...something. If any of them are willing to take it. Not a happy tale, but gritty and painful and real.
Nothing But Blood by Pablo. Rated NC-17. Nonconsensual sex.
Wishverse. Nasty and evil and squirmily hot. Vamp!Xander gets assigned to babysit a certain peroxided guest of the Master's -- and they play with the Puppy. There's Vamp!Willow/Xander in here too, but she's not really part of the group fun, nor does she participate in actual smut, so this one stays on the slashy side of the page.
Triad by Mihreia. Rated NC-17.
Something of a guilty pleasure -- it's a WIP that I suspect isn't likely to be finished, it requires quite a bit of suspension of disbelief, might have benefited from a beta-reader in a few places, and it ends on a cliffhanger. Ouch, you say. But... call me shallow. I love this one anyway. Vamp!Xander stumbles from an AU-of-an-AU Wishverse where the Master is dead and the White Hats and vamps are still at war, into vaguely post-4th-season mainverse. Edgy and funny. Snark and sex and power politics between Spike and the two Xanders, in what is basically an extended PWP.
Spike's Boys and Spike's Boys II by Wordsmith. Rated NC-17.
I can't believe I forgot this one on the first go-round. Due to a little spell-kerfluffle of Willow's, the twin Xanders of The Replacement are back in business. When she tries to fix things, Spike gets in the way. Silly and fun, and more Spike(s) and Xander(s) than your little heart could desire. (I could have done without the Xanders being referred to as Suave-Xander and Sweet-Xander, but it didn't hold me back for long.)
Entra Mi Casa by Pablo. Rated NC-17.
PWP sequel to a Xander/Graham series, but can definitely be read on its own merits. Graham and Xander invite Spike over to their place to thank him for his help in said previous series. They have impressive ways of showing their gratitude.
The Education Series by Pet. Rated NC-17.
AU Season 5-ish. This is primarily a hot and humorous S/X love story (with much of the sweating and glistening), but includes multiple encounters with Devon/Oz, including a final free-for-all that heats up the house like nobody's business. Pet manages to give Devon a personality while still giving us the flaky rock-whore As Seen on TV (TM). Love her, please.
A Matter of Control (and its sequels) by Kay. Rated NC-17.
AU Season 4. The bite of a rather unique demon leaves Xander in a dangerous sexual predicament. Spike comes to his rescue, followed shortly by Angel and Doyle. Somehow, in the course of saving Xander's life, the four of them forge a bond that's much more permanent than just sex. (Though there's certainly plenty of that.)
by Esmeralda. NC-17.
AU Season 4. Xander needs rescuing, and only one thing will prove to the demons who've kidnapped him that he's not free for the taking. Spike and Xander's one-time deal becomes something more -- but when that pesky little chip becomes a problem, Spike has an interesting solution -- Angel. A youngish-written Xander for his actual age, but the sex is hot, the lurrve is sweet, and there's *lots* of it. One of the early pivotal S/X series, this also contains Spike/Angel, Spike/Angel/Xander, Angel/Doyle, and one heated encounter that blurs more boundaries than you can shake a pointy stick at. Esmeralda is currently working on a new story in the series.
Too Many To Count
Just The Guys and Just More Guys
by Jae Kayelle. NC-17.
Sheer silly PWP fun in Giles' brand new bed. Theoretically Giles/Angel with a smidgen of Spike/Xander, the insanity soon becomes exponential and ridiculous, which is completely the point. By the end of the second story, almost every available non-evil male in the Buffyverse has joined the party. It is, to be archaic, a hoot.