Spike tricks buffy

I remember reading a fic where i think it was christmas time, spike sends a gift/ outfit to buffy and she thinks its from angel. There's a note inside saying where to meet, when she get there its spike not angel. They sleep together and at the end willow tells angel about the gift but he says it wasn't from him and goes to spikes crypt and sees them together

sounds like:
Dangerous Liasion by vampirische liebe
it's on Elysian Fields

Yup that's it, Thanks