Contouring is when you slightly rotate the pin in a circular motion, spreading the impact area of the hammer all around the pin head. This flares the edges of the pin thereby tightening the scales. But you do have to be careful, to tight and you'll crack the scales. Also, you can slide off the pin and damage the scales also. You just want to use enough power on your stroke so you would be able to stick your finger under the hammer head and not hurt yourself. Any harder than that and you risk the chance of bending the pivot pin, and that will cause your blade to go off center and possibly hit the scales while closing, causing damage to the edge.