Playing with secure intonation relies on having a stable hand frame.
Set up the hand starting from the 3rd finger to find a good balanced position. Make sure the wrist is in line (straight line along back of hand, wrist, forearm), and that you do not push the wrist out when you use the 4th finger.
Tapping the finger ensures that the hand supports the finger's fall into the correct position for accurate intonation.
You can also set up the hand from the 4th finger.
- Set Up Left Hand from 3rd Finger
- Set Up Left Hand from 4th Finger