I call this the S-Method because that is what it was referred to when I first heard about this handy trick of getting a thicker yarn (3x thicker) from thin yarn. And I continue to call this the S-Method because it serves as a useful reminder for how we start this process.
This is one handy and short video (by Briana K / YouTube)
love all your work, I have bought your gloves patterns and made them for my daughter she loves them, you are very talented. I have used the S method I know it as Navajo ply Regards Jan from Australia