I acknowledge this table from the Internet.
Blocking all sensations
Let prana move up
Bliss as if ant crawling
In this verse, Shiva leads from pratyahara, starving the senses of their food, to dharana, focusing on one sensory perception, to dhyana, focusing on one thought, and finally to samadhi, disengaging from the mind. All these four states comprise the internal part of the ashtanga yoga practice.
Here, the first step is to stop feeding the senses. We have five sensory gateways of perception: eyes, ears, skin, tongue and nose, through which we see, hear, feel, taste and smell. In addition, we have five active sensory input based actions: speaking, grasping, moving, excreting and procreating. At one level, pratyahara requires disengaging from the external stimuli that feed these ten sensory windows. Sitting in meditation with eyes closed helps to still the mind because almost 75% of sensory inputs arise through the sense of sight. Not seeing and not moving helps in disengaging the senses from the stimuli.
At the next level, we need to disengage the mind from the senses. Manas, the mind part that controls inputs from the senses may be starved of stimuli, but chitti, the memory part of the mind, may still keep feeding the mind with stored inputs. This is why even if you close your eyes, plug your ears, clip your nose and tongue and suspend yourself without touching a thing, you will still keep watching internal videos and audios, loud and clear. This is also why those engaged in rituals, seemingly engrossed in what they do, snap out of their seemingly focused concentration at the slightest sensory trigger.
Ashtanga yoga, therefore, recommends two more steps: focusing on one sense, and then on one thought so that the mind become one pointed, from which one point it’s easier to disengage the mind into a no mind consciousness. Every one of these 112 verses of Vigyana Bhairava Tantra address one or another of our senses of perception and action to help focus as dharanas. From this focused sensory attention moving into one focused thought is the next step of dhyana, or meditation.
One can use any one or a combination of Shiva’s techniques to focus on one sense and disengage from the others, then move away from the sense perception to a thought behind that sense. For instance, using the technique of this verse, one can focus on the root energy center, muladhara chakra, and visualize that energy to move up the spinal pathway sushumna, if one is trained in the technique. The focus will be on the sense of feeling of the energy moving up. Eventually, the sensory focus can be shifted to the thought of the energy moving up. Finally, one disengages from that thought as well.
One can use techniques such as shanmukhi mudra to achieve a similar result. Those who are experienced, can use breathing techniques to initially focus of the sense of feeling the breath on one’s upper lip portion, then the thought of the pranic energy and finally disengage from that as well.
Don’t take the ant crawling expression of Shiva literally. One does feel a sensation, a subtle internal energy manifestation, as the energy is aroused. It can be a movement as if an ant crawling, a churn, breathing or even a subtle pain.
The safest path to ant energy arousal is through one of the breath awareness and body awareness techniques already discussed in this blog. I would not recommend even shanmukhi and such other mudras, bandhas and asanas can be dangerous when applied to arousing the kundalini.