Hi all, I have been reading here for a while but have never posted. I just wanted to ask you guys a simple question. I just bought the fatracker digital fat tester. My question may seem silly but I am not sure how to use it. It tells me that I have to pinch about 3 inches of my skin. Now how hard do I pinch? and do I press the button once the calipers touch the skin or do I have to apply some extra pressure?