Yes, relax your tongue and place it in the centre of your oral cavity—not too far forward, not too far back. Yes, that is correct. Part your lips gently, feel the rush of air from your lungs, and force them across your vocal cords.
Ventilate. Restlessly, relentlessly, as if going for a kiss. The tongue must be in the proper position; air must flow between the teeth; exchange your breath: back and forth, inhale and exhale, until you make an unintentional noise.