In the below talk Bikhu Analayo, the author of the great Satipatthana book, mentions that he visualizes his own death right before he goes to sleep every night.
Inspired by Analayo, I have been experimenting with visualizing my last moments, as well as meditating in a cemetery by my house. Surprisingly, this seemingly morbid practice has caused me to feel strong mudita (appreciative joy) for all of us that get to experience a human life.
Below is my understanding of the typical last few days of life:
1)You begin to withdraw from others.
2)You are usually sleeping, or unconscious.
3) Then your muscles relax and you become incontinent.
4)Then your nails, and lips turn blue and face becomes sunken;
5) Liquids build up in your throat and lungs causing your breathing to sound gargled, otherwise knows as the "death rattle".
6) Your breathing slows down to one breath every 30 seconds or so for a little while, and finally you take your last breath and peacefully let go.
Analayo talk:
http://dharmaseed.org/teacher/439/talk/14214/
When this concentration is thus developed, thus well developed by you, then wherever you go, you will go in comfort. Wherever you stand, you will stand in comfort. Wherever you sit, you will sit in comfort. Wherever you lie down, you will lie down in comfort.