[PeterPrinciple]

The process is chillingly simple: Descending on a fallen foe— living or dead—the victor hops on his or her back, places one or both knees between the victim’s shoulders, wraps the hair around one hand and traces a circle or semicircle around the crown of the skull with his knifepoint. Using his knees for leverage, he wrenches the hair —skin and all—from the skull, often to the accompaniment of a distinct popping sound. When carried out by an experienced person, the actual deed is accomplished in a matter of seconds.

https://www.historynet.com/1876-george-custer-not-scalped-yellow-hair-first-scalp-custer.htm

[billorites]

"places one or both knees between the victim’s shoulders, wraps the hair around one hand and traces a circle or semicircle around the crown of the skull with his knifepoint. Using his knees for leverage, he wrenches the hair —skin and all—from the skull, often to the accompaniment of a distinct popping sound. "

I hate it when that happens.