Answer:
I will disappear every time you say my name.
I am three simple words everyone wants to hear. Three simple words such simple words and yet...life changing...
Though desert men once called me God today men call me mad. For I wag my tail when I am angry. And growl when I am glad.
I'm very tempting, so it's said. I have a shiny coat of red and my flesh is white beneath. What am I?
It's in your hand though you can not feel it. Only you and time can reveal it.
Some women don't like to be called that, yet every woman wants one. It cries and makes a lot of noise, but smiles and gurgles when you give it toys.