Oh. My. God! This was a stupendous fic! I think I've been dying for a Snupin fic just like this but didn't know it until I started reading. The characterizations are superb, and I especially love how you made Lupin able to hold his own against Snape while remaining believable. Snape's awkward discomfort, Lupin getting more and more frustrated as he misreads Snape's signals (or maybe not, right?), the zinging dialogue, the great atmospheric descriptions -- this totally ROCKED!!!!
There are so many good scenes in here, but the one that really got me was at the end when Lupin announced "you may not need anyone but I do, and you're it) and sat down beside Snape and forcibly hugged him. (Kind of makes me think of that 'Engineers Guide to Cats' video with the 'corporal cuddling'.)
The sex scene was marvelous but I think the build up was even better. I seriously love me some UST, especially when Lupin's so frustrated he's about to bite something and Snape's like 'whut?' Oh gosh, just a delicious fic and *exactly* what I didn't know I was looking for. Definitely going in the 'faves'. Thank you so much for writing this.