That's a good one. See how the cords open up when she inhales? That's what I'm talking about when I say you hold the air back at the base of the chest with ribcage expansion. If you hold your cords open like that, like you do when you inhale, and keep them that way, AND you are holding your breath with your mouth open, your cords open, AND your chest expanded, then you are holding the air back simply by way of chest expansion. THAT is the feeling of holding the air back at the base of the throat that so many people go "tell me how to do that" about. That's how. Otherwise, you would be holding the air back at the glottis (vocal cords) itself. That is too much pressure to force upon the glottis. It needs the help of the ribcage expansion, the act of "holding the breath" with all apertures open.