According to Osho, the roar of 'Hoo' rides on breath, which permeates every pore; thus the sound reverberates not just in the heart or navel but throughout the body, striking sexuality that is concentrated at the sex center yet diffused everywhere. This forceful sonic 'hammering' cracks the inner seed, freeing virya (sex-energy) to rise upward, catalyzing deeper meditation.
Shouting “Hoo” strongly sends vibrations with your breath through your whole body, hits the sex energy, and helps it move upward into calm awareness.