How should you position a patient to use a mucus clearance device?

How do you properly position a patient to ensure effective use of a mucus clearance device? Is there a specific posture or angle that should be maintained for optimal results? Additionally, are there any precautions or adjustments that should be made depending on the patient's condition or the type of device being used? Please provide a detailed, step-by-step explanation of the ideal positioning and any relevant considerations.