Power Play by islandsmoke
Wow. Like, wow.
I have to say this-- I am absolutely so not into BDSM. In fact, I'm really not that into smut, period.
This fic delves deep into the psychological recesses of BDSM, and of Snape, Lupin and Snupin. I think it is the most singularly convincing Snupin I've ever read. I enjoy the pairing in general, but usually have to make a real effort to put my disbelief in a box and lock it away-- this was so perfectly paced and evolved so naturally that I didn't have to do that.
What's more, not one damn thing in it squicked me, which is a bloody fucking miracle. *is generally a very sensitive reader* The entire thing is handled so tastefully.
So, I clicked on the link because Smoke wrote it, but 'so and so wrote it' is never enough to get me more than a couple of paragraphs in.
Even if you don't like Snupin, and even if the warnings make your eyebrows climb, I'd recommend this one.
So go read.