There are several basic subdivisions of what is called the Yoni Puja. There are Inner and Outer pujas, and each of these can occur in either an ordinary or a secret form. Apart from this, again, the Yoni Puja is subdivided into three categories, each of which can be indicated by one of the following terms: adoration, magic, and meditation; with the latter being the most secret one. Inner, in this context, refers to the fact that the practice is being done inside one's head, using visualization, rather than visibly in the outer, material world. Outer, of course, then refers to a visible ritual of one or more persons before an object or a woman. The latter type of Yoni Puja is often performed in mixed groups, although sometimes only women or only men may be attending.
In an ordinary outer Yoni-puja, performed with a sculpture of the Devi (Skt., Goddess) or with a woman (Skt., stri) as her living representative, five liquids are poured over the Yoni. In literature, such libations are often simply interpreted as an offering to the divine, but the actual practice of a Yoni Puja shows that there is more involved than that. The five liquids, representing the five elements of Indian cosmology, are poured consecutively over the Yoni, and are collected in a vessel below the thighs. The final mixture, resulting from the five libations and empowered by such direct and intimate contact with the (living) Goddess, is then consumed by those present at the ritual. This means that once these substances have been offered to Her, She, having purified and energized them, returns the offering as a gift (Skt., prasad) to her worshippers. In this system of associations, the element Earth is represented by yogurt, the element Water by actual water, Fire by honey, Air by milk; and Ether is represented by one or another type of edible oil.

Elemental symbolism such in in this example, permeates all or most forms of worship in India. In other types of puja, different materials are used, yet with the same underlying symbolism. Any traveler to India will have seen pujas performed in which actual fire and water are used together with burning incense (smell, earth), a peacock feather (air) and a conch-shell (sound, ether) that is blown continuously amidst the sounds of many bells and cymbals. Equally, those attending a puja will usually offer five different fruits or other substances to the deity, thought to present in the sculpture; things such as milk, flower petals, rice or whatever. So we can see that the Yoni-puja, in that regard, is completely embedded in mainstream Hinduism; however special and secret it may otherwise be.
In the case of a Yoni Puja practiced with an object, for example a sculpture or with a natural object such as a coco-de-mer, the energies imparted to the prasad (Skt., divine gift) depends on how well and by who the object has been consecrated and sanctified.

In a Yoni Puja performed with a living women, indicated by the terms stri puja and rahasya puja, the merits of the practice depend on the type of woman who takes part. How strong the transference of power is, from the yoni via the liquid materials to the participants, is very much dependent on the woman who serves as the focus of worship. Of all stri pujas, the most simple or 'low' level worship is that of a young girl of 16; known as Kumari Puja.
Although the number 16 is regarded in India as the number of perfection, and although she will first be consecrated by a priest, the girl's "perfection", i.e. her nubility and beauty, does not lend her any of the powers that are possessed by a woman of higher degree. In this case, the woman at the center of worship is a yogini, here used as a title for an initiated woman who, as such, is also much more mature.
Again, the powers transferred from her Yoni are comparatively weak when compared with those of the woman who is the channel of power in an even 'higher' type of practice. Here, at the summit of all Yoni Pujas, the woman representing the Goddess is a true and full-fledged guru and in this case, the powers transferred from her Yoni to those who worship are most strong and most suited to raise the consciousness of those who take part in this ceremony, to those who eat or drink the mixture of liquids that have been purified and empowered by contact with her naked yoni, her flame of intelligence.
Among the secret outer pujas, divided into adoration, magic and meditation types, the first two are most easy to describe. Before the visible Yoni, either of a living woman or an image of the Goddess, the worshippers offer their general prayers (adoration stage) or beg her, while chanting mantras, to grant them wishes of all kinds (magic stage), wishes that range from "please cure my m other" or "please give me a son", to the even more egocentric "let me have success in business and make me rich". So what we see here quite clearly, is the fact that there is nothing here that could possibly be classified as 'sexual' or 'obscene'. What these people do is and what has been and is being done by millions of people everywhere, is asking for a little attention from the divine for their personal sufferings, problems and ambitions. Such prayers are offered and encouraged in most religions, the only difference being that some direct such prayers to an invisible but jealous father-figure in heaven, some to a naked, bleeding and crucified man, some to his weeping mother; and again others - as in the Yoni Puja - to the source and seat of life, to the gateway that connects the inner womb of gestation with the outer reality of human life.

Above, when I mentioned local or sectarian varieties as opposed to basic structure, I was referring mainly to changes in the succession of steps and actions taken. Somewhere, someone, may start with the element earth rather than ether, or enact fire before water. These differences, however, as every intelligent reader will recognize, do not really matter. What matters is the dedication and single-minded attention of the practitioner(s), combined with the attraction inherent in the object of veneration. It is this combination which enables the raising of one's awareness and which provides the potential for liberation inherent in these rituals. What is further needed, naturally, is the ability to do all of this with a deep love and respect for the specific powers of women, for the seat of life, for the Goddess.
Something worth mentioning here - and remembering - is the fact that in all of the above, I've not described any practice of any especially esoteric sect, or of any so-called obscure group of infamous Tantrics, but a rather standard practice belonging to mainstream Tantric Hinduism. With the 'secret' information given above, passed on to me by someone who has seen these rituals and participated in them only a decade ago, we have actual 'proof' that the worship of women, of the Goddess and the Yoni, has survived - at least in India - from its roots in paleolithic times up to the present.

Other Tantrics, embracing and utilizing ALL manifestations of life in order to find enlightenment, often go much further. Also here, in a religion that the researchers and scholars of the early 20th century often found too 'shocking' to report honestly, the Yoni Puja is known, though in some texts we find mention of it under alternative names such as bhagayagya. Besides the obvious - that a unique and special one-pointedness can be achieved by contemplative concentration on the Yoni - it becomes clear from sacred texts such as the Yoni Tantra that the major aim of a Yoni Puja is the ritual creation of a subtle energy and/or liquid that is called yonitattva, or, during menstruation, yonipuspa .
Whereas the yogini is an initiated woman specifically trained not be become sexually aroused by all the attention to her body, and especially her Yoni; in these Tantric practices the sexual energies are awakened on purpose. Here, the Yoni is not only adored and worshipped, but also stimulated and excited, sometimes even penetrated; depending on which holy scripture a specific sect follows. No mixture of yogurt, honey or oil are consumed by these worshippers. The most esoteric of Tantrics, in their most secret modes of worship, consume the juices of love produced by the woman/Goddess - or by mingling the female juices with those of the male. Two thirds of the thus generated 'divine nectar' are then mixed with wine and are drunk by the congregation; the remaining one third is offered to the Goddess.

Sometimes, this type of Yoni Puja is also celebrated with a menstruating woman, producing an even more powerful liquid, known as yonipuspa (Skt., flower of the Yoni). Although this is a practice forbidden by most texts and within many sects, it is specifically advocated in the above mentioned Yoni Tantra.