Step back and counter attack drill (Jum Sao + punch)

The drill here is to help develop the skill to be able to step back whilst maintaining connection to the opponent's centre of gravity and just as importantly maintaining one's own structure. Also how to immediately step forward to counter attack after stepping backward rather than constantly retreating. An example this skill might be needed is if you had to deal with a high load of incoming force that your stance can not withstand. Later in time with more practice of developing a good siu nim tao structure, you should not even need to step back because you have developed the skill to feel and absorb/dissipate incoming force.