I have been doing this to our son when he was a baby without knowing that it actually was a thing. With my son it worked most of the time, however when I tried doing this to my daughter it never worked, all it did is that it made her cry even harder. The spot I usually massaged was the purple (lower abdomen) area. And I did that with both babies.
Perhaps my daughter’s problem was not her stomach, who knows. But I think my son was actually having lower abdominal pain, I remember he was a very gassy baby lol.
Bottom line, I don’t know if my experience can confirm that this theory is correct or not, but if your little one is a bit fussy this is something here’s worth a try!