When Remus Lupin arrives to teach Defence at Hogwarts, Severus Snape finds himself saddled with a LOT of potion-making – not to mention an irritatingly cheerful and intelligent new colleague. Why won't everyone just leave him alone to enjoy his newly flourishing sex life? (Snape/Lucius, very slow-burn Snape/Lupin. PoA timeline, AU in places.)