Buffy has sex with Spike while he's asleep. Spike thinks he dreamed it.

So, all I remember about this fic is that Buffy and Spike were sleeping (that means actual sleep sleeping) together and Buffy woke up. Somehow they ended up having s3x together. Buffy was awake but Spike was asleep. I suppose it was like sleep walking for Spike, but sleep s3xing instead. For a while Spike just thinks he dreamed the whole thing. Buffy doesn't tell him that they really did have s3x until quite a bit later. I'm not entirely sure if this was a vamp/slayer fic or an all human fic. I also think Buffy might have become pregnant, but that could be a total random and incorrect detail. Thank you for any help.

nea
In Saber Shadow Cat's "Humanitus," Spike wakes up one day, human and goes to Buffy for her help. It takes place during season 3. Spike has been in love with Buffy for a while and in one scene while staying at her house, in her room, has a dream that she comes back from the doctor (is pregnant in the dream) and he asks if the doctor says it is ok for them to make love. Buffy over hears him dreaming, talking in his sleep and talks back to find out more. The end up making love, but Spike thinks it was just part of his dream.

Buffy gets pregnant and ends up telling Spike many months later what happened and that the baby is his. It is one of my favorite fics.

nea
Could it be Humanitis by Sabershadowkat (aka Sabershadowkitten)? It´s on her site, part 7 has such a scene.

That's the one! Thank you so much. It had been driving me crazy for months not being able to remember what fic it was.

Link:

Humanitis by Sabershadowkat

http://www.sabershadowkat.com/buffy/humanitis.html

Spike comes down with a case of humanitis.
Post Consequences

There is a PG-13 version as well:

http://www.sabershadowkat.com/buffy/SBuffy.html