The heraldic image above actually comes from the Hastings Hours (a private devotional book) in the British Library . Evidently, the Hastings family coat of arms is comprised of argent a maunch sable (or, black sleeve on a silver background). So the negative space between the sleeve that looks like the Playboy Bunny is just pure negative space. And that oddly shaped black thing is a sleeve, like the ones on a shirt but imagine a long, swooping medieval sleeve.
The golden writing around the blue belt (actually the symbol of the Order of the Garter ) says Honi soit qui mal y pense : Shame be to him who thinks evil.