Actually, you don't want to lay on the ground; you want to sort of squat/sit-on-your-ankles, kinda like this: 
(And be sure to ground your metallic [and electronic] items.)
I have read that too.
If your hair does that, immediately lie down on the ground.
Or perhaps not - if you are lying on the ground and there is a nearby lightning strike, the potential difference between your head and feet could be enough to kill you. It might be better to crouch down low rather than lying down.
Actually, you don't want to lay on the ground; you want to sort of squat/sit-on-your-ankles, kinda like this:
(And be sure to ground your metallic [and electronic] items.)
You may hear a sound similar to bacon frying,
Again hit the dirt!