From Discworld MUD Wiki
The facing command will tell you which direction you are facing, or which direction another person is facing.
Typically, you will be facing directly away from the exit you came in from. However, you can use the turn command to face a different direction.
Forms of syntax available for the command "facing": facing facing <living>
The direction you are facing will change what relative exits do. In other words, if you are facing north, then going "forward" will cause you to go north, while going "backward" will cause you to go south.
It also determines the direction in which you wimpy.