I don't have one, so I'm not quite answering your question (what people who own them use), but then, you weren't asking if you should carry a Derringer type pistol and that is what most people answered so...
I'm also in the that wouldn't be my choice camp, but I can see the allure. As an occasional thing, a nod to history, I could see the desire to do this from time to time (in the same way a SA revolver would), and it would have one good practical use. As a "get off me gun" that is backup to a larger gun it could have some utility. Like a revolver, at contact distances, when you are grappling/wrestling with your attacker it won't ever be pushed out of battery like an auto can, but in .40 or.45 caliber in a gun that easily fits in your pocket (my choice if I was to do it, like yours, would likely be .45ACP due to lower cost than .45LC).
For such an old school choice, my choice of holster would definitely be leather over nylon or kydex. My first thought was a pocket holster. But a quick search for holsters available for the Bond Arms Derringers brought me to the Bond Arms Driving holster, an on the belt crossdraw holster that looks interesting. Buy one for your weak hand and it seems to me that it would fit the most practical use of a Bond Arms Derringer well as your strong arm would likely be occupied with the struggle with your assailant. Another option, this does seem like a gun that would work as well as possible unholstered as someone mentioned above, though a holster will help position the gun vertically in your pocket so it is easier to draw.