Please note that this is the Narutopedia's article on the video game ninjutsu. If you are looking for the article on the ninjutsu in the anime then you should head to Earth Release: Earth Dragon Bullet.
A Water Release user performs Water Release: Water Dragon Bullet Technique, Gaara mixes his sand with it or a Earth Release user adds earth-chakra to it, the dragon shoots mud at the opponent.
The Earth Dragon part of this technique would usually be pronounced as mogura and is actually the Japanese word for mole. However, given the nature of this technique and similar techniques from other elemental lines, the pronunciation and meaning are likely meant to be Earth Dragon and Doryū.