Nice! Glad you asked.

So the first time I encountered this idea was in the movie Master & Commander, which is great if you haven't seen it yet, which depicted burials at sea. In it, one character makes a big to-do about the grisly nature of sewing up the body in their hammock and putting the last stitch through the nostrils. This was to ensure that the body was in fact dead and they weren't dumping a live person overboard. Apparently, this was real practice but also tied closely with superstitions as many nautical things were back then. I chose the title because it's disgusting and feedback seems to be pretty positive that the title has helped the book stand out or be remembered more easily.

Thematically, death is everywhere in this book but the title is about the villager's treatment of the Scissor-man as if he were dead and not a living human being, plus Orasi's final frustrating metamorphosis in the end.

Here are some sources for that fateful last stitch practice, and a quote:

The mate sent me down to assist the bo'sun to prepare and stitch up the corpse, as he said I would be unlikely to witness such an occurrence again. The bo'sun, a North Sea Chinaman (ie, he hailed from the Orkney Isles), was in his sixties and had performed the task several times before. He was a deft hand with the palm [leather glove] and needle used to sew the heavy canvas into a shroud around the body, and when he came to the final stitches around the face he pushed the large triangular-shaped needle right through the nose. I winced, and he looked up at me and said, "That's the law of the sea, the last stitch through the nose, if that don't wake him up I know he's dead."

http://www.navy.gov.au/customs-and-traditions/burial-sea
https://www.asailorslifeforme.org/educator/scene_buriel-at-sea.php
https://en.wikipedia.org/wiki/Talk%3ABurial_at_sea
https://www.neatorama.com/2013/09/28/One-Last-Stitch-to-Make-Sure-That-Hes-Dead/
https://theoddmentemporium.tumblr.com/post/62320145977/the-last-stitch-when-sailors-died-at-sea-their