There are many methods and techniques by which kuṇḍalinī energy can be activated. There are two possibilities in kuṇḍalinī activation. One is involuntary activation, when immense devotion transforms into love for Parāśakti; Parāśakti means the Power of Divine. Second is activation through practice. Former is far safer than the latter, as automatic ascension happens due to Śaktipāta (descent of Her Grace). When She showers Her Grace, the aspirant undergoes instantaneous transformation and during this time, kuṇḍalinī ascends on its own. During activation through practice, the depth of devotion is extremely important. Without the highest level of devotion, it is not advisable to practice kuṇḍalinī meditation and even if practiced, it could lead to some inexplicable syndrome, which is often called kuṇḍalinī syndrome. In the case of Śaktipāta, Divine energy descends from the cosmos into the body of the aspirant through an orifice known as brahmarandra at the top of the skull and this Divine energy enters through the spinal cord and activates the dormant kuṇḍalinī energy at the perineum. Only during this type of activation, extraterrestrial visions and decipherable sounds are possible. One can consider himself/herself as a blessed one, when Śaktipāta is showered, which instantaneously makes one realize the Self. Unless one is thorough with the procedures and other intricacies of kuṇḍalinī meditation, it is always better to refrain from practicing this. Role of a Guru is extremely important in kuṇḍalinī meditation, as many times during practice, one will have several doubts.
Before we proceed further, it would be wise to read this interpretation given under Lalitā Sahasranāma 110. “Kānci Paramācāryā in his magnum opus ‘Voice of God’ observed the following about Kuṇḍalinī yoga: “Kuṇḍalinī yoga is not the only path available to the seeker.  Choose any path other than it, adhere to it with a mind that is one-pointed and with faith and sincerity.  As you advance to a high state on this path, your breathing will change automatically and it will be similar to that of one practising yoga-s.  You may even be aware of it; the breathing will change on its own” and after saying that one’s breath will undergo modifications, he says, “....the movement of breath will impinge on the nerves in the roof of our head and touching the feet of Ambāl (referring to Śaktī) create a flow of ambrosia.  Even in worldly life when we are in ecstasy of delight our breathing stops and we faint.  In this, there is reflection of the emotion experienced by us during kumbhaka (holding breath).  During this time we exclaim: ‘Ah, I feel cool in the crown of my head.’  This also means that a tiny droplet of the ambrosia has trickled on the nerves in the crown of the head. I have said this to show that even by following the path of devotion you can have inward experience of sublime nature.”
There are two methods to activate kuṇḍalinī through practice. The first method is the proven method in which beginning from mūlādhāra, every higher chakra is activated step by step. This takes a longer time to activate higher chakras. In this method, meditation is done at every chakra, so that every chakra is not only fully activated, but also well balanced. But there are some risks involved. Activation of chakras can be done only with the help of prāṇa and consciousness. In this method, while moving from one chakra to the next higher chakra, there is a possibility that the prāṇa does not move through suṣumna and instead could move through iḍa and piṅgala, causing side effects and most of the times, any damage caused to the system is difficult  to repair. Such effects are known as kuṇḍalinī syndrome, which cannot be explained as this will vary from person to person. One common thing in kuṇḍalinī syndrome is that, it is bound to affect the nervous system and brain leading irreparable psychic state. However, if proper foundational practices such as prāṇāyama, bandha-s and mudra-s are perfectly practiced, chances of manifestation of syndromes could be less. However, it is always advisable to practice under the direct guidance of a Master/Guru. Whatever being discussed here is applicable only to those who have attained perfection in various practices discussed in the previous parts (1 to 9).
The second method is to activate the pineal gland situated very close to ājñā chakra. If ājñā is activated fully, pineal gland gets automatically activated. This is comparatively a safer method, as directly activating ājñā chakra will avert kuṇḍalinī syndrome, as in this method, there are least chances of kuṇḍalinī ascending through either iḍa or piṅgala. Further, in this method kuṇḍalinī is not awakened straightaway, as a result prāṇa first purifies suṣumna to enable kuṇḍalinī at the time of awakening to traverse through suṣumna without any blocks. Prāṇa not only cleanses suṣumna, but also blocks iḍa and piṅgala during ascension of kuṇḍalinī. This action of prāṇa is known as prāṇa-utthāna.
Let us understand what prāṇa-utthāna is. As we know, prāṇa is the vital force or life energy and utthāna means ascension or causing to ascend. Prakāśa (Self-illumination) is Śiva and Śakti (svātantrya śakti of Śiva) is Vimarśa (Self-consciousness of Śiva). When Śiva is Light, it is Śakti who makes His Light get reflected on worldly objects created by Her. It is only the reflection of His Light and not direct Light. His direct Light is known as Kālāgni, the fire meant for annihilation of the universe. In order to avert annihilation, Śakti casts a veil around this Light and this veil is known as māyā. By praying to Her, She removes the veil of māyā cast by Her and when the veil of māyā is removed, Śiva is realized. The veil of māyā can be removed only by Her Grace known as Śaktipāta (descent of Her Grace on the aspirant). Kuṇḍalinī is the subtlest and yet, the most powerful form of Parāśakti. She manifests in the form of three types of kuṇḍalinī and this is known as Her triple emission. Vimarśa can also be explained as emission, as emission means the act of causing to flow forth. Parāśakti emits the Light of Śiva to create and sustain the worldly process. Her emission happens through three aspects of kuṇḍalinī - śaktikuṇḍalinī, parakuṇḍalinī and prāṇakuṇḍalinī. In Her non-emitting state, She merely remains as dormant kuṇḍalinī, though She is highly potent and in this form She is known as Śaktikuṇḍalinī. While lying in dormant state, She encompasses parakuṇḍalinī and prāṇakuṇḍalinī. At this point, we are not going into more details, as this will involve further discussion of Trika philosophy. To understand this in a simpler way, at the time of formation of foetus, prāṇa gets deposited in mūlādhāra just above kuṇḍalinī. During prāṇāyama and other practices, this prāṇa rises up from mūlādhāra chakra and if practice is perfect, it enters through suṣumna and cleanses the innermost nāḍi called citriṇī, also known as Brahma nāḍi. Only when citriṇī nāḍi is purified, ascension of parakuṇḍalinī will happen in the way it should ascend. It is only parakuṇḍalinī, that ultimately unites with Śiva at sahasrāra. However, Śaktikuṇḍalinī continues to remain in kula-sahasrāra (below mūlādhāra). Kula-sahasrāra is Parāśakti’s Abode. She remains there in Her subtlest form Kuṇḍalinī and akula-sahasrāra is Śiva’s Abode. When their union takes place at sahasrāra, it signifies the union of Śiva and Śakti and when this happens in our body, it signifies realization. It is also said that when this union takes place, one’s karmic account is totally annihilated, but many do not subscribe to this view. If this view is accepted, the explanation for jīvanmukta becomes obliterated. It can be said that at this stage, a practitioner becomes a jīvanmukta, provided he is able to perpetually sustain in this stage.
At this point, we understand that kuṇḍalinī does not ascend in the beginning, but it is only prāṇa (prāṇakuṇḍalinī) from mūlādhāra chakra that goes up to cleanse citriṇī nāḍi, through which parakuṇḍalinī travels to meet Śiva at sahasrāra. This cleansing process will not happen if nāḍi śodhana prāṇāyāma (discussed at the end of part 3) and other practices described in other parts are not followed meticulously.

Energizing ājñācakra:

By this practice, kuṇḍalinī will not ascend. This will activate prāṇa-utthāna to clean citriṇī nāḍi; during this process, not only citriṇī nāḍi is cleansed and purified, but also iḍa and piṅgala are blocked. This prevents any possible kuṇḍalinī syndrome.
Take the sitting posture as discussed in the previous parts. Do yogic breathing. Breathing has to be slow and deep. First few rounds of breathing may not be slow and deep. When breathing becomes slow, fix the attention on the ājñā chakra using śāmbhavī mudra (with closed eyes). This is not exactly śāmbhavī mudra, as there is a modification. In this modified form of mudra, which is neither śāmbhavī mudra nor nāsāgra dṛṣṭi, first fix the concentration on the pineal gland (ājñā chakra) using both the eye balls (pineal gland is discussed in part 9 of this series). After a minute or two, shift the attention to anāhata chakra (heart chakra). Continue to fix the attention there. Without moving the awareness from heart chakra, inhale and exhale. At the time of inhalation, visualize that cosmic energy is entering into the body and at the time of exhalation, visualize that citriṇī nāḍi is being cleansed. Both these visualizations are to be done on the spinal cord. When our attention is fixed at anāhata chakra, following happen.
ajna chakra
This image explains this practice. Violet colour star just above the central point of eyebrows is the ājñā chakra, behind which pineal gland is situated. Two downward black arrows indicate the focus of the eye balls on the heart chakra, which is in green colour. The red colour upward arrow is the upward movement of prāṇa cleaning citriṇī nāḍi. It can be observed that when prāṇa ascends from the base chakra, it traverses through ājñā chakra and then to sahasrāra. This process is called prāṇa-utthāna or ascension of prāṇa.
1. As we are focussing on ājñā chakra, it becomes fully active.
2. As we are not using any force to awaken the kuṇḍalinī, it continues to remain in its hibernated state.
3. Deep inhalation and exhalation work on prāṇakuṇḍalinī at mūlādhāra chakra to become active and as a result, prāṇakuṇḍalinī moves up through citriṇī nāḍi. When prāṇakuṇḍalinī enters citriṇī nāḍi, activities of iḍa and piṅgala are annihilated. When iḍa and piṅgala are blocked, the only way for prāṇakuṇḍalinī to move up is through citriṇī nāḍi and thus, kuṇḍalinī syndrome is averted.
4. When this is perfectly practiced, the passage of kuṇḍalinī is completely cleared of any blockages and when parakuṇḍalinī ascends, it ascends with ease and to higher chakras.
5. When prāṇakuṇḍalinī moves through the citriṇī nāḍi within the spinal cord, it goes up to sahasrāra and cleanses the entire path of parakuṇḍalinī.
When the path of Kuṇḍalinī is cleansed, Kuṇḍalinī can be activated with ease and confidence.