What they are talking about is the creation of the Merkabah 'light ship'. This is created automatically if you can master the practices, which are generally complex and difficult...so difficult that even those that teach and write about it cannot actually do it. I give a simplified technique that does work, called 'Two Tubes' that can be used to generate the 'light ship'. This is a vehicle that forms around the astral body that allows for extended OBE with good recall, and the ability to travel in time and space at will.

While tantra may be an interesting way to approach this, I cannot see how it could succeed.

You must consider the 'bias' of writers, as bias creates filters that color information according to the beliefs of a person.

See my books for the Two Tubes method, Astral Dynamics, and, Energy Work...and my video course, Raising Kundalini.

peace, robert