I've done done it. You have to know yourself, really know yourself, and them understand and embrace The All. This permits you to leave the body and material things because they become immaterial.

The problem is that you might not at all like what you find. For example, the first time I did it I found my leg being peed on by a wiener dog. I knew at once that this was a test, of course, but by then it was too late: I had to go wash dachsypee out of my pants legs. But anyone can achieve it: embrace the Valkyries, let them take you with them, and know that beyond Ragnarok lies True Nirvana, where you can fight, feast, drink, and wench (or man) to your heart's content, knowing that if you are slain you'll be alive again because you are one of Kali's soldiers and that you are marching with the One-Eyed One who has the two ravens to guide him.