What is a mushing glide?
Why is it called a mushing glide?


The aircraft is not cleanly cutting through the air. It is "mushing" through the air at a high angle of attack creating lots of drag and a slow forward airspeed.


  In this glide, does the aircraft points its nose less (or more?) steeply?


The aircraft has its nose pointed up (less steeply) than a normal glide.


  How does it steepen the descent?


The low forward airspeed and high drag creates a high rate of sink relative to the forward motion. Low forward speed and relatively high sink rate means the descent will be very steep. A fully stalled condition would be an extreme example of a "mushing" glide.  


  low AOA (pointing slightly above horizon) causes it.


pointing the nose slightly above the horizon is still a High Angle of Attack, not low AOA.