so I never did find the last story I was looking for (link to search is
here if you're wanting to look) but in the meantime I've added another to the list of one's a can't seem to find. what I remember: kagome gets some kind of poison scratches on her back and sesshomaru takes her back to his palace to see a healer. The healer suggests having her ingest/drink sesshomarus poison in order to gain an immunity to poisons and thus heal her back. thanks for reading this and let me know if it sounds familiar!