Making the change from Ving Tsun Sticky Hands to Taijiquan Pushing Hands should be an easy one. Of course, a fire drill is always easy, until one has a real fire in their backyard. Thus, to understand this change one must make a few adjustments in the way they think about things.
First, the Sticky Hands of Ving Tsun is usually done with a certain springiness in the limbs. Someone pushes on your defense, and you give away enough to guide them, and then spring into the opening created. This is a generality, and there is a lot more to the drill, but it is what we must focus on to make our transition.
Second, the pushing hands of Taijiquan is actually a bit misnamed. It should be called ’emptying the whole body,’ simply, one must give way until the opponent over pushes and thus unbalances himself. This summation of Pushing Hands is quite inadequate, but, again, we are attempting to bridge from one exercise to another, and this is what we must focus on.
Now, we go from giving way with a certain ‘springiness’ inherent in the movement, to a giving way (emptying of) with the entire body. One drill is giving way with the arms, and the other is to absent the whole body from incoming forces. Thus, if one can take the ‘springy’ quality out of the arms, and just concentrate on emptying the arms and the rest of the body, the transition can be accomplished easily.
When an opponent strikes and you feel that the springing quality is not sufficient for the situation, or you just feel like converting into Taiji, match the velocity of the incoming strike, turn the waist, and guide him past. It goes without saying, that he should not feel you manipulate him. It must be a guidance not of flesh to flesh, but of hair to hair. Your touch should be so soft that he doesn’t fight it.
At this point you should be able to question whether you are doing the art of Ving Tsun, or the art of Taiji. The only difference, you see, is in the depth and height of stance. You may be standing in a two legged stance (goat riding) or in a single leg stance of some height, versus being in the deeper shifting stance that is common to Taijiquan.
So we come to the crux of the matter. Give way in sticky hands and let the attacker fall through (or into a lock). Or give way in pushing hands, and then use springiness.
We are not really talking large differences here, merely subtle differences that are, truth be told, inherent in either exercise should one take the time to study gung fu long enough and with a correct eye to the potentials. The whole point here, is to help people who have been trained in one art to adjust to new training and new methods, and new (sometimes just stated differently) awareness. That is how you make the transition from Ving Tsun Sticky Hands to Taijiquan Pushing Hands.