The installments appear in order at AO3; if you follow the links to my journals (@Dreamwidth, @InsaneJournal, @LiveJournal), the installments appear in reverse order.
I hope you enjoy the Thoroughly Inappropriate Series!
ETA: I've added the following description of the series to its page at AO3 and its listing in my master list of fics and fests: Severus Snape is a troubled man doing his best to keep a promise under the most trying of circumstances when he finds himself drawn to Daphne Greengrass. Although he knows that it would be thoroughly inappropriate to act on his attraction to her, his struggle to retain his self-control grows more difficult as he becomes increasingly bound to Daphne in unexpected ways. (Please see the individual installments of this series for their ratings and warnings.)