Looking for a fic set sometime between seasons 4/5, where Buffy's powers have advanced.  She breaks Riley's hand while fooling around and she has sex with Spike to test whether or not she can be with a human.  Spike claims her during sex, she accepts, then Skip shows up to bind them together...spuffiness ensues.  Ringing any bells?

I recognize the fic...but have no idea where I read it or when.  I'll keep thinking & let you know if I remember. :D

-clarityfades

I know it isn't it, but it sounds like Kari Mouke's Normal, where Buffy accidentally kills Parker during sex, and Spike helps her cover it up, actually a pretty funny fic.

I remember reading that fic. Possibly on here. You might do a search by season and see what comes up.

I think it's "favours" by Pale Rider