I've never heard this term but the second I read it I knew exactly what it meant. I get this when trying to sleep. I will be peacefully drifting off to sleep and suddenly I feel like I'm falling down through my bed towards the floor and I hear this loud whoosh/rumble/explosion. The two are so jarring that no matter how many times it happens it can't just be ignored. When it happens over and over in the same night, it actually makes my ears ache. It is the major cause of my insomnia for the last 15 years.

Over the last 3-5 years I've experimented with Polyphasic sleep (short naps rather than one long sleep period) as well as better sleep hygiene (using red light to signal when it's sleep time) and even more recently binaural beats (though sleeping with headphones is awkward at best).

Somehow it feels somewhat validating to know there is a term for this and it's a known phenomena. I wish it was something that could be treated though.