Abstract: A typical embodiment of the device consists of a convex form (for example, a hemisphere of radius similar in size to a lacrosse ball) connected to a bracing crosspiece by a threaded screw shaft. The form is attached to one end of the shaft, the bracing crosspiece is threaded onto the shaft, and a knob is affixed to the other end of the shaft. The device is used by placing the bracing crosspiece across the lacrosse head with the ends of the crosspiece under opposite sidewalls, and tightening the form against the stringing to the desired depth by twisting the knob and thereby screwing the threaded shaft through the crosspiece. The invention provides a means of forming and maintaining a pocket in new stringing at a chosen position along the length of the head and to a desired depth. A single crosspiece of variable length, or interchangeable crosspieces of various fixed lengths may be used to accommodate different lacrosse head widths.