My friend was sick and needed an IV drip.

The one giving him the injection was an intern nurse.
She poked and prodded for a long time but couldn't find the vein.
He was in so much pain, grimacing and gritting his teeth.
With no other choice, he called for the head nurse.
The head nurse had great technique.
She smoothly inserted the needle into the vein in one go.
Then she immediately pulled it out.
She handed the needle to the intern nurse and said:
"Did you see that clearly? Now you try again!"