Dr. Hamilton from Santa Monica, who has been caring for newborns for over 30 years, said he has taught parents to successfully use this technique at home.
Now it's your turn.
An unhappy baby who was soon happy again thanks to Dr Hamilton's technique
The doctor asked someone to film him working his magic on unhappy babies who had just had an injection. And it really is very simple.
1. Fold the baby's arms across her chest and secure her gently with one hand.
2. Hold the baby's bottom with your dominant hand so you have a secure hold.
3. Rock her at a 45 degree angle gently. Move her bottom from side to side.
Dr. Hamilton said the majority of the time, this will make the baby quieten down.
"If they don't, think about two things - they might be ill or they might be hungry," he added.
"This is helpful for babies of two or three months of age, after that they become a bit too heavy."
Within three days of being uploaded on 29 November the video accrued 1.2 million views.
Watch the full tutorial video below.