I've raised three kids and was working with a guy who brought his sixth child to the office to take care of while his wife was away with work. His child was a month or two old and was pretty fussy and co-worker seemed to be at his wit's end. I asked him if he had tried the "off" switch, which he had never heard of. I started calmly and regularly stroking the baby's forehead from the mid-forehead to between the eyes. Kid was out like a light in less than a minute. Co-worker asked me how I knew that trick and I asked him how he didn't given this was his sixth kid.

I wonder if the "rub dust" method originated with something like this but used the dust component as a means of justification/explanation to people so that they would be focused on calmly applying the dust rather than going overboard with the stroke on the forehead due to frustration.