I'm looking for a fic I found a while ago.
set just before "once more with feeling"
spike & xander have a ONS I'm not sure if anya's in the picture or not.
but I do know that when Sweet comes to town that xander sings about "my demon from Hell" in stead of his & anyas "i'll never tell"
also instead of buffy going to spike for info It's xander & the authors also rewriten "rest in peace" so that it fits the situation.
I'm pretty sure I found it on Spander files