Folklore is riddled with dragons, phoenix and unicorns.
We are not interested in such creatures. To the best of our knowledge they are make-believe.

How do you emulate a dragon? Have you ever seen one?

Chinese martial arts have long been inspired by natural forms of movement and behaviours.
The form posture names reflect this quite clearly: stork spreads wings, snake creeps down, repulse monkey, part wild horses mane...

It is common for people to literally copy the mannerisms and actions of an animal.
Monkey is a common example of this, as is preying mantis.

Sifu Waller does not wish to behave like an animal. We are humans, after all.
The aim is to simply emulate the spirit of the animal.
We are interested in capturing the essence/nature/characteristics/quality of the animal.

The key to '4 ounces of pressure' is stopping as soon as you experience resistance.
If your body is loose and floppy, you will not want to push or use your arms for strength.
Sifu Waller places great emphasis upon not pushing against force.
We regard strength versus strength to be a major folly.
Once you can feel the difference between using your weight and using force, it is easy to realise why.

Maintaining central equilibrium enables us to use the three dimensions easily and skilfully.
If we slouch, lean or slump, the power is dissipated immediately.

The key to sustaining central equilibrium is to remain within your natural range, and to avoid exotic, flamboyant postures.
Low stances and wide stretches reduce your stability significantly.

The human skeleton is strongest when we are upright. Your tai chi needs to reflect this.
If your stance is long and low, it reduces your ability to move.

The highest level of tai chi practice is high stance and small circle. In high stance and small circle you can conserve your energy to a maximum level.
(Yang Jwing-Ming) 

To incapacitate an opponent, aim whenever possible to compromise their ability to maintain central equilibrium.
Invariably this is accomplished by encouraging them to over-commit, to lose their centre, to forsake their own balance.

Form without shen is simply a hollow pattern.
You may have the positioning, the movements and the timing right, but that is all.
Knowing the 13 postures will help to develop your sense of jing, but something is still missing.
Performing the applications is not enough either.

Intention is a start, but you need something more. You need spirit. Shen.

People push for things in various aspects of their lives.
If things do not go their way, they push, and then push a little harder.
When learning tai chi, pushing is fruitless because the skills will only come once you stop pushing.

The attitude of not pushing is called wu wei.
For it to really affect your life, it needs to extend beyond the class.

Moving qigong is much easier to practice than form.

The coordination is simpler and the health benefits more immediate and tangible. Form takes much longer to learn and quite a long time to actually perform competently.

Anyone can do qigong. There is a lot less to think about. The exercises are focussed and clear. You need not complicate matters by thinking about self defence applications or any other concerns.

It is also important not to get caught up thinking about qi. Let the energy take care of itself. Keep your mind on the exercise. Intention leads the qi and the qi leads the blood. Breathe and relax.

Once you are competent at qigong, take what you have learned into form. Form is essentially moving qigong with extra features. The extras include increased balance and coordination, martial application and energy emission.

In motion the whole body should be light and agile,
with all parts of the body linked as if threaded together.

The qi should be excited; the shen should be internally gathered.

The postures should be without defect,
without hollows or projections from the proper alignment;
in motion the form should not become disconnected.

The jing should be rooted in the feet, generated from the legs,
controlled by the waist, and manifested through the fingers.

If correct timing and position are not achieved, the body will become disordered
and will not move as an integrated whole; the correction for this defect
must be sought in the legs and waist.

The principle of adjusting the legs and waist applies for moving in all directions;
upward or downward, advancing or withdrawing, left or right.

All movements are motivated by mind, not external form.

If there is up, there is down; when advancing, have regard for withdrawing;
when striking left, pay attention to the right.

If the mind wants to move upward, it must simultaneously have intent downward.

Alternating the force of pulling and pushing severs an opponent's root
so that he can be defeated quickly and certainly.

Insubstantial and substantial should be clearly differentiated.
At any place where there is insubstantiality, there must be substantiality;
Every place has both insubstantiality and substantiality.

The whole body should be threaded together through every joint
without the slightest break.

Tai chi is like a great river rolling on unceasingly.

Wardoff, rollback, push, squeeze, pluck, split, elbow, shoulder are equated to the Eight Trigrams.
The first four are the cardinal directions; the second four are the four corners.

Advance, withdraw, look right, look left and central equilibrium are equated to the five elements: metal, wood, fire, water and earth.
All together these are termed the Thirteen Postures. 

(Chang San-feng)
      

Softness and yielding are yin qualities. They require physical sensitivity and awareness.
Instead of pushing, you must yield into the opponent.
This is accomplished by allowing your body weight to move.

Pushing hands is an exercise in yielding; you relax your own body enough to allow the opponents force to move you and then you shift your weight in order to move them.

Should your partner present more than 4 ounces of resistance during the exercise, you must stop pushing immediately.
Once you learn not to push against solidity, your physical tension will start to fade and your body will begin to use gravity creatively.

'Reasonable force' requires you to be cautious in how you treat an attacker.
Do not make it an emotional event.

Be practical and expedient.

Your aim is to incapacitate temporarily. It is not to exact justice or vengeance.

Sets are not self defence.
They are fixed pattern, and serve to train accuracy, positioning, timing and movement.

The skills they teach can be taken into self defence if they manifest under pressure without contrivance.

In practice, the sets are about habit.
They encourage a certain way of moving, a habitual approach to attack.
This is what you take into self defence.

When facing a single tree, if you look at a single one of its red leaves, you will not see all the others. When the eye is not set on one leaf, and you face the tree with nothing at all in mind, any number of leaves are visible to the eye without limit. But if a single leaf holds the eye, it will be as if the remaining leaves were not there.

 (Takuan Soto) 

The conventional use of strength involves the application of force at a given, specific moment in time. If the aim is to break an arm, the individual exerts for a moment and the effect occurs.

The problem with this is that it is tiring. It wears you out.
Exerting the muscles is not very energy efficient because most of the effort accomplishes nothing; it feeds back into you when resistance is encountered.

'Internal power' is altogether different. Exerting never occurs.
The limbs are imbued with strength at all times, so an arm break would be performed with no more force than raising a glass of water to your mouth.

Where does the power come from?

It comes from unifying the body and projecting a wave of kinetic energy (jing) throughout the entire structure as and when necessary.
It is the wave that breaks the arm, not the local muscle strength.

If you lack composure, you will not see what is right in front of you.
Being calm is utterly essential.
You need to remain detached, emotionally aware and at ease.

This is the real reason why white belt syllabus students practice 'escapes'.

As soon as you use tension, you have failed.
Even if you eventually prevail, it has cost you an unnecessary amount of effort and is not tai chi.

Correct use of alignment, timing, pressure and positioning will enable you to skilfully defend yourself.