Related Clues:

• Opening
• Aperture
• Vent
• Mouth
• Hole
• Hole in the head?
• Vent, e.g.
• For CIE, I look for an opening
• A bodily opening.
• An opening, mouth of a cavity
• The mouth of a cavity
• Bodily opening, mouth of cavity
• A bodily cavity
• Mouth of a bodily cavity
• Either the whole sound of it, or when it's frozen