While maintaining the downward force on the Shepard's Hook in my left hand palm, I use my pointer finger to apply pressure, from behind, to the fur and the thread. The thread pushes into the skin of my finger pad while the fur stays out on the top of the finger pad. This action produces a "vee" in the fur and presents both ends of the bundle for trimming. Here, I'm only trimming the butt ends to the right of the thread. Just slip the scissors up the finger surface and clip...not your finger...the fur !