Metaphorically speaking, the energy of a chakra is very similar to the energy of a typhoon (tropical cyclone). Chakras are not muscle points, not chi points along chi channels, they are points of void, points of nothingness. In other words they are not points where we can feel it through sending chi energy there (like voluntary contracting the otherwise almost involuntary muscles or tendons) there. Actually in some chakras, sending chi will be counter-productive, for example, sending too much chi to the third-eye chakra will result in dizziness and heavy-headedness. The structure of typhoon is similar in this respect. The centre of the typhoon is calm. The energy of power consists of wind circulating around the centre at high speed. The power of chakra energy is the same. Here, we talk about orbit and field energy. The benefit of this conception is that, like everything else discussed in this site, it serves the objective of promoting sound (more efficient and more effective) training. Pedagogy is what I am interested in, rather than arm-chair philosophizing. Theory with a purpose, and a well defined purpose.
In a typhoon, wind travels in circular movements and can also be perceived as a field of high energy. This is a good metaphor for chakra energy training. The first stage is to create an orbit or high traveling energy. I shall use the solar plexus chakra as an example. The location is upper abdomen in the stomach area. Psychologically it is associated with confidence and in control. The orbit is the belt channel. Here the meditator shall visualize a belt channel horizontally embracing the middle part of our torso going through the solar plexus. Another orbit required is the Du Mai at the back and the Ren Mai in the front forming a closed loop - a belt channel in the vertical front/back plane. Prior training is required before building up the orbits. These two orbits defined our torso, in Neidan lingo: cauldron.
After the two orbits are built (established or activated), chi is made to fill the rest of the surface (and at the later stage, inside as well) of the cauldron. After the cauldron has been established, chi will be field like instead of orbit like. The chakra as void is always there. And it is the time when true chakra meditation begins. Meditation on the void. As for the psychological aspect, I shall leave it to other posts.
Who said chakra meditation is simple and easy?