A rice bag (sometimes rice mush) is sort of like a Chinese sandwich.  There are other Chinese snacks that are actually probably more sandwich like such as char siu bao, but I can't really think of any other western analogue.  In its most basic form it is made of glutinous rice, meat, and seasonings (soy sauce).

The rice is seasoned and worked a bit to make it bind better, like kneading dough except there isn't any gluten to work.  The result, similar to a coarse mochi is wrapped around the cooked meat filling in the form of a tetragonal disphenoid and wrapped with bamboo leaves and string.

This package is then steamed to impart the flavour of the leaves to the rice and eaten.  I was taught that the proper way to eat a rice bag is to remove the string and unwrap the rice, if you haven't a plate you can just leave it sitting on the unfolded leaves.  Use the string to cut the parcel into mouth sized pieces and eat with chopsticks.  Alternately, if you're in a rush, there's no reason to be a little informal and eat it like a sandwich using the leaves as a wrapper.

The flavour is a combination of sweet, smoky, and the flavour of the filling.  It's similar to Chinese sticky rice, in fact it is more or less sticky rice in a wrapper.

DMan has a recipe under glutinous rice that calls for lotus leaves rather than bamboo leaves.  Either will do. The rice bags I bought tonight were wrapped in bamboo, but the ones I ate 2 nights ago were in lotus leaves.