Lust/Lack. Excessive sexual desire, and lack of desire.
The opening of the second chakra often brings with it an excessive, extreme sexual desire and sensitivity, with spontaneous orgasms occuring unexpectedly, and extreme sexual reactions to unusual stimuli, such as observing flowers being pollinated, or bacteria dividing under a microscope.
The second chakra holds issues of sexuality, reproduction, emotions and relationships. The desire occurs when the kundalini energy impacts on blockages that are repressive issues about sexuality, and to increase the sexual energy to break through any blockages held in this chakra.
While some Kundalini teachers advocate abstinence, I am not one. I believe in the Wiccan ideal, "All acts of love and pleasure serve the Goddess." Sexual tantra has been used to facilitate the awakening process, for millennia. Sex with an awakened person can cause awakening. (Something to beware of, once one reaches the stage of being Shakt-contagious... awakening can be horrific for the unprepared, so be discerning in your choice of lovers.)
I do advise caution, discernment and care in following these sexual desires, as some desires may come up that are inappropriate, even illegal to express. Some people may experience desire for sexual contact with minors, children, animals, or a desire for violent sexual contact such as rape.
It is best to simply observe such inappropriate desires, and accept them. Generally, they are not indicative of an actual shift of sexual orientation, but are appearing to release issues and are symbolic of a desire for unity with all things. The appearance of sexual dreams or fantasies about children does not mean one has become a pedophile. It is symbolic of a desire for unity with innocence and purity, and more love for one's own inner child.
The appearance of fantasies about sexual acts with animals is symbolic of unity with nature, and with one's own animal nature. Violent sexual fantasies of rape are usually simply a manifestation of unconscious anger being brought up to be resolved and released.
When these fantasies or visions appear, do not act on them inappropriately, or judge yourself harshly for having them. So long as they are not directed towards any particular individual, allow the visions or fantasies to play out in your mind, and masturbate to release if you feel guided to do so. The phase will pass sooner, if you do not offer resistance or allow yourself to wallow in feelings of shame or guilt.
With more conventional, legal desires, depending on your circumstances, it can be healthy and affirming to find a suitable partner, or partners to express them with. Do be clear about your goals with your sexual partner, do not mislead them into thinking the acts or relationship is a precursor to an extended relationship committment. This phase will pass.
If you can act them out with your current marriage or relationship partner, so much the better! Do be aware that they might get unexpected side effects or reactions to facilitating your emotional release, and support them as best you can.
A long term side effect of the second chakra opening, can be bisexuality. This is nothing to be concerned with, some believe that bisexuality is natural for humans, and exclusive hetero or homosexuality is aberrant. Simply put, "love knows no gender."
You may find that once the second chakra is cleared, your love is directed towards individuals rather than sexual traits or gender issues. Your attraction is based on someone's personality or energy, rather than whether their plumbing is male or female. The spiritual energy of the persons you are attracted to, is more important than the physical gender characteristics.
Whether you act on your bisexual desires or not, is up to you.
Later on in the process, the intense sexuality of the second chakra reverses, and there may be a notable absence of sexual desire, spontaneous celibacy. The second chakra is cleared, and so does not offer any resistance to the energy moving through it towards the higher chakras. Life itself, every day offers a greater and more all-encompassing bliss than what you could achieve be even the best sexual experiences, previously.
If the lack of desire is an aversion to sex, then there is still blockages to be cleared.
Ideally, sex is still pleasurable and enjoyable, but the driving sexual needs felt previously, have passed.
If you are married or in some other long term committed relationship, I encourage you to continue to be sexually active for the sake of your partner, allowing them to express their desire with you, and welcoming their advances. You may need to focus on your second chakra, to be responsive. Letting the energy build there, instead of rising. Sex will feel different, when no longer motivated by one's own desire, but is still rewarding and enjoyable intimacy that has an overall beneficial effect on the body vessel.
There are many schools of tantra that have specific exercises to redirect sexuality to the higher chakras. Pursue these if you are drawn to, but usually these exercises are ways to awaken the Kundalini; once awakened, follow your inner guidance about what to do. Sticking with control based exercises after Kundalini is awakened, can be a form of resistance. There are also some schools of thought that have a kind of scarcity consciousness about energy, believing it must be conserved. If you consider your expressions as a gift to the Goddess, you will find what what is given to Her, comes back multiplied. In any case, simply staying grounded will usually provide all the energy you need.
In my school, Kundalini is awakened by Shaktipat, and the design for using sexual energy to enhance the process is quite simple.
Think of the genitalia as the fire, and the pleasure moving through your body, as the smoke. Stoke the fire with sexual stimulation, but put your focus on the smoke; The pleasure and energy rising up through your torso and chakras as the stimulation continues. Your attention to the smoke will encourage the energy to rise above the second chakra to bathe and open the other chakras.
Delay the release of orgasm as much as possible, for either genders by stopping stimulation just before you reach the point of no return, resting for a while then continuing the stimulation. As this process continues, men learn to have orgasms without ejaculating, and women become multiply orgasmic. One may also discover the bliss of endorphin based orgasms, which are similar to sexual orgasms but the afterglow lasts longer. It also serves to expand your limits about how much sexual and spiritual energy you can handle.
The best manual for learning to attain this type of extended orgasm, is
Eso: How You and Your Lover Can Give Each Other Hours of Extended Sexual Orgasm by Alan P. Brauer, Donna Brauer, Richard Rhodes
and the updated version,
The Eso Ecstasy Program: Better, Safer Sexual Intimacy and Extended Orgasmic Response; by Alan P., M.D. Brauer, Donna J. Brauer (Contributor), Richard Rhodes
Some people find good value in the books by Mantak Chia; I find that some of the exercises can be useful, but they advocate a peculiar scarcity consciousness about energy, with all the concepts about the need to conserve and recycle energy.
Through the experience of grounding you may discover that energy is infinite, once you connect to source.
As a side note: awakened persons radiate kundalini energy, this is referred to as the Shakti-field. Unawakened persons may experience this shakti-field as sexual energy, and either be very attracted to you, or think that you are desiring them. Negotiating this effect can be a bit of a minefield, and great discernment is required. You may find persons of either gender spontaneously declaring their love for you; this effect is not genuine, but you will have problems convincing them of that without appearing to mock them! The attraction is functional; it is simply how Goddess manipulates their perceptions so that they pay attention to what you have to say, and be receptive to your energy.
Generally, it is best to avoid intercourse with such smitten people, as they will assume that it means their love is requieted and there is a possibility of permanence. So long as you are kind to them without taking sexual advantage of their vulnerability, their attraction will pass when its purpose is done, and a warm mutual respect and friendship will remain. Your kundalini charisma will attract people, but it is not really fair to take sexual advantage of those who are drawn to it.
Particularly for those who are professional healers, the best way to explain your clients attraction to you, is by comparing it to how some people fall for their Doctors or psychiatrists... and explain that you have similar professional ethics about no sexual contact with clients. Most people will understand and accept this, and in the long term will be grateful for your professional reserve, even if it is frustrating, in the short term.
If you are interested in playing the Guru-svengal role, you may choose to become a mentor-lover to those who are drawn to you in this way; be aware that once they have learned all you have to offer, they will move on and you may end up being the one feeling used and taken advantage of. Teacher-student relationships are never meant to be permanent. Students graduate and move on.
It is best, and healthiest to choose a relationship partner who is at your own level of awakening and experience. Such relationships have the best chance of long term success, as you both grow and evolve together. I caution against love spells and visualizations to attract a partner. Instead use surrender, and ask Goddess and your Divine beloved to send you someone.
Let your relationship with your Divine Beloved be your first and primary marriage, serve that, and have none before; in time they will choose a life partner for you. I can tell you from personal experience, that such an "arranged marriage", arranged by the Divine will be a better match than you could ever choose, for yourself.