You're probably best off dipping them in the dark chocolate.

Melt in a bowl of hot water, and keep it there, so it stays liquid. Chopsticks are the best tools for this, and you will need to dip them twice to fully coat them. Use good dark chocolate, 70% cocao or so, and the rum won't dilute the chocolate too much, but do drain them off for a little (30 seconds or so) while before you coat them.

Let them set on a wire cake rack if you have one, or a smooth ceramic surface, ie a plate, if not.