Fortunately, the Epley maneuver is very effective, if done correctly. Unfortunately, if done incorrectly it can worsen the symptoms. It's all about identifying in which semicircular canal are the otoliths before moving them.
I can fully block smells or breathing by doing something that feels like inflating a zone between the top of the mouth and the nose. When speaking it will sound as if I am pinching my nose without hands. Comes in handy when having to face horrible smells.
I assume everybody can do it but many don't know how.
https://www.reddit.com/r/TooAfraidToAsk/comments/ysd5o2/is_i...