Hannora was kind enough to send me Boy Smell Nice, and now I'm searching for another Beer Bad fic I read loooong ago.

It has Buffy jumping Spike, of course. I don't remember the exact order of things, but I remember Buffy then wakes up as they are having sex somewhere like a crypt or sewer or abandoned building, she realises it's Spike/a vampire she's having sex with (sees his black fingernails, notes his lack of heartbeat) and she headbutts him in the nose (on point for them). But even though the spell is broken, they end up having more sex and at some point go back to her dorm.
Willow comes looking for Buffy, but doesn't realise Spike is in the bed with Buffy. Willow falls asleep (on top of Spike's duster) on her own bed.
I think she wakes up to Buffy and Spike having sex — I think they realise she's there and Buffy is mortified and wants to chase after her, because I think Buffy and Spike have a fight over it and then he leaves. They reconcile at some point though. I remember Spike thinking the witch must have slept on his coat, because it smells vaguely of spices.

That's everything I can remember, I think! Anyone have the faintest idea about which fic I'm rambling about?