How 2(to) make a scratching noise

Scratching noise that DJs makes while turning the disc is cool right? Maybe for some people it is, but to make a noise like that it sounds difficult. BUT once you get to know it, it will be much easier. The skill that I'm going to tell you is called crab scratch. First you have to put your thumb on the middle joint of index finger from the the hand. From this you can make a simple v shape, you have to make sure that it has airway. (the v shape has to be clear) Then you have to put that v shape contact with your mouth. The thumb has to touch one end of your lip and the V shape has to be contacting on the middle of your lip. Next thing you have to do, is just breath in. First you have to breath in easily, and make a sound. You have to get the hang of it. After that if you are comfortable with that position and sound that yo are making, just practice to make the sound louder in to real scratch.