Peng

Without peng, the small san sau will not work.
You need inherent peng in every posture and manifest peng when counter-attacking.

The simple 'evade and attack' methodology of the small san sau makes it quite easy for a student to address peng from the onset.
There are no unpredictable attacks.
Correct countering will ensure ample opportunity to test peng.
If your peng is present you will immediately destabilise the attacker using the neutralising arm, and further their instability with the counter-strike.

The absence of peng will be evident through blocking and crumpling, and the use of unnecessary force.