I'm looking for a story I know I read on this archive. It's post-war, and very kinky. SS and HP are playing with bondage, SS has HP in a sling in the corner of the potions classroom. The detail that stands out in my memory is that one of the toys SS uses looks like a stone snake, and it comes alive when he puts it in HP. He then casts a concealment charm, leaving HP bound there while SS works with some students, so HP has to keep quiet and still or risk a student seeing him like that. Does this ring any bells?