Hauling means to increase the overal line speed by additional acceleration of the fly line thru the guides. Done for the forward AND back cast, we call it DOUBLE hauling.
A lot of fly casters only think about their line hand movement when talking about hauling and how to adjust it. This video shows why hauling is done by both, rod hand and line hand movement. The key is to understand that we move the stripping guide via rod hand away from the line hand and opposite.
This video also shows the affect of thrust to hauling speed.