If you look at the video, you can see I use my two hands most of the time.
There are three reasons for using both hands:
•For ambidextrous grooming
•For grooming with both hands simultaneously
•To help the grooming hand by stabilizing the skin

Finger angle

Your choice of hand depends on the angle your fingers have in relation to the skin you want to reach.
When the fingers are straight, you have to push to apply pressure.
When they are curved, you pull.

Pulling is much easier and you can put more force.
Both angles has their advantages and inconveniences.
Often, using one hand to groom a specific location will result in an uneasy or uncomfortable position. Try your other hand.

Hands taking turns

Grooming is a physical effort.
It takes its toll on the performing members.
You get tired.
The pressure you put, the repetitive movements and the awkward positions all contribute to your discomfort over time.
Grooming sessions can last hours.
Using only one hand, your forces would weaken after a while.
Simply alternate your work in two different areas, each accessible with the other hand.

Using both hands at the same time is a normal grooming procedure, though moderately used.
This is an extension of ambidexterity.
Grooming is done with both hands simultaneously.
Most of the time, one hand mirrors the actions of the other (symmetrical), but sometimes, each hand can act independently.

Symmetrical two-handed grooming

Since your body is symmetrical, it makes sense to groom similar locations on both sides at the same time.

Often, four finger scratching stokes are used on both hands.
This works best for non-critical areas where big resurfacing jobs are needed.
Your scalp is a good example of where this technique can be applied.
With your four nails digging on both sides of your head, simply move both hands back and forth simultaneously.
The grooming strokes on both hands are synchronized and their movements are almost identical.

Comparing sides

One interesting aspect of symmetrical two-handed grooming is that you can feel the difference in the skin condition between your left and right sides.

You can spot problems this way.
If a crossing or fold has grown abnormally, the same location on the opposite side may not present a similar transformation.

Double grooming

Grooming two different areas of your body simultaneously is quite rare.
It still happens occasionally when you are already grooming a region and you feel an itch or urge to groom another.
Your attention wanders between both actions and the results are dubious.
Still, it works for a few seconds.

The idea is to use your non-grooming hand in support of the on-going action.
If you want to groom your forehead, raise both hands to the location.
One hand starts grooming while the other assists.
We can separate helping duties into two categories:
•Holding and stretching the skin
•Underpinning

You can groom some areas easily because your skin is already held tight to whatever is beneath.
But if you try to groom areas where it is loose or where it covers a thick layer of fat,. you will find that the skin’s flexibility prevents proper grooming.
Your nail caves into the skin and it moves along with your nail.
Use your other hand to pull the skin tight

You can use several fingers and grasp the skin in any way in your quest to keep it from moving.
Both hands move in concert, one grooming, the other holding-up the workspace.

Stretching the skin

Each finger on the helping hand can have its own action
Some may just hold the skin in place while others may be pulling on it.

If you use two fingers to pull in opposite directions, you can stretch the skin on both sides of your grooming finger.

It's a pity to put such an important technique at the bottom of this chapter, but where else?
I use underpinning close to 50% of the time.
My grooming would get nowhere without it.
It is not an easy procedure to develop. It took me months to gradually master it.
The still image on the video player shows me underpinning my chin.

Underpinning theory

You use underpinning in your everyday life when you put something hard beneath a material you want to work on.
This is necessary because it lacks the rigidity needed to resist your moves.
Putting a mass behind it makes working on it possible.

Squeezing the skin

You trap a piece of skin between your two fingers.
One finger acts a a solid workplace, the other grooms.
A band of skin is captured by this action.

Use underpinning where the skin is loose and not tightly attached to the body.
The wobbliness may be due to a thick coat of subcutaneous fat.
Some areas, such as your buttocks and cheeks, are almost impossible to groom without using underpinning.