This is a linkpost for https://www.thelastrationalist.com/memento-mori-said-the-confessor.html
This is the same 6500-word essay linked in the OP. It might be helpful to note that (I think) the relevant part is the very last two paragraphs. And you say there that you are not sure what Becker meant by practicing dying. The concrete method you describe is:
I'll lay down in bed and imagine that I'm about to die in the next 5-15 minutes. ... When I first started doing this I found it very distressing, but over time I've gotten a lot more capable at soberly considering the end of my existence.
Ok, I imagined it. I shrug.
I would prefer to not die, and most ways of dying range from unpleasant to dreadful, besides the fact that they end with death. I have had a narrow brush with one of those, and seen it happen to a few other people, and of course I know that it happens to everyone. That pretty much covers my attitude to death and dying. But I get the impression that this is not what you or Ernest Becker mean by "fear of death". Do you mean something more than this?
The fear of death acts as a sort of master key for introductory rationality concepts. Examining the fear of death ties all the rationality basics together into a coherent framework, including:
Small brain: Don't think about death.
Shining tomagraph: "After I die I'll go to heaven because I'm a good person."
Expanding brain: "God isn't real, I find it more comforting to think that this isn't all a test."
Galaxy Brain: Practice dying.