This is one for fans of boots and bondage – two things that aren’t normally combined in this way. I’ve heard of thigh highs, but never armpit highs. Now I come to think of it, I’m surprised no enterprising fetish manufacturer has produced a leather bondage sack that’s shaped like a boot. I can’t think it’d be to hard to modify a standard sleep sack to look like one. The intersection between bondage lover and boot lover is probably a decent size market.
I found this via Pitt Prickel’s twitter feed, where it’s attributed to Rudolf Schlichter.