“I had a friend over and we were playing outside and he got like a cut on his hand or something and just somewhere in the back of my mind I remembered hearing if you take, you know, the back of a knife, like a pocket knife, the not sharp edge and you just kinda gently brush that over top of the cut or if it is a small burn or any sort of small little injury, like that, it will help kind of soothe the pain.”

The informant grew up in North Carolina and lived there his entire life there until moving to Los Angeles around three years ago, where he currently resides. He does not remember exactly where or when he first heard this practice (he is not sure if from the television, the radio, or from someone directly), but recalls thinking of it when he was maybe four or five when his friend and he were playing outside.
As a child, he remembers always having a pocket knife on him, causing him to immediately pull it out when his friend got the cut in order to gently brush the knife over it to try and make him feel better. His friend did not trust him at first, but eventually allowed the informant to try it, ultimately making him “feel a lot better.”
The informant also admits that he is sure he tried it on himself at some point because he was always outside playing with sticks and such as a child.
Since then, the informant remembers looking it up and receiving some sort of conformation that this worked at some point, but has yet to be able to find it years later when looking it up again.

The informant relayed this to me while in the passenger seat of his girlfriend’s car as she drove us all back up to Los Angeles. I have known the informant since he moved to Los Angeles.

In my opinion, I believe the practice of using the knife to be partially mental as well as physical. My idea follows the idea of “the placebo effect,” where simply being told it will make you feel better, you start to feel better. However, I think the back of a knife, most likely cool and smooth, naturally would feel good on a burn or a cut and would soothe the pain even if only for a little while.