According to the Christian gnostics the astral body is of two types. A lunar astral body and a solar astral body. The lunar body is made up of various egos that need to be eliminated while the solar astral body is developed through White Tantra known as sexual transmutation or alchemy.
All people have a lunar astral body those people who work on themselves can use this as a vehicle of consciousness. The lunar body is a body of egos, inferior to the solar astral body which one acquires when they've achieved Buddhahood or Christification through the arcanum A.Z.F. or sexual magick.
Apparently sexual magick has been used by all great masters including Jesus. White Tantra is practiced to raise the kundalini through all seven of the energy bodies. Apparently this is the"hidden teaching" of all mystery schools, and it is the difficult path of immortality.
There is a lot of interesting info here.
http://www.gnosticteachings.org/index.php?option=com_joomap&Itemid=88
It's a gnostic Christian site so try not to let any disdain for religion overtake your quest for spirituality
I recommend the courses on Dream Yoga and the Transformation of energy.
http://www.gnosticteachings.org/index.php?option=com_content&task=category§ionid=5&id=73&Itemid=58
http://www.gnosticteachings.org/index.php?option=com_content&task=category§ionid=5&id=88&Itemid=63
This is some fascinating stuff. As always take what you read with both an open mind and with a grain of salt.
I'm just resurrecting this post because it has useful information.