The following except is lifted from Kali Kaula by Jan Fries. Check it out on Amazon.
"Over the last decades, a host of ill-informed would-be gurus have popularized the idea that Tantra is simply spiritual eroticism. It proved to be an idea that sells. Countless new-age prophets are selling costly ‘Tantric Workshops’ where people receive a bit of much needed basic sexual education. What sells as ‘Tantra’ in this market has very little to do with the original. Massage, overcoming shyness, sensuality, odd postures, retaining ejaculation, producing an erotic atmosphere, Reichian body therapy, bio-energetic exercises, and the like are well and good, but they are certainly not what the Tantrism had in mind. In fact, if you accept the new age vision of Tantra as the real thing you may arrive in a mind space that promotes hedonism, sensuality, and worship of the body as an end to itself. I suspect that those Tantric lineages that actually promote lovemaking in their program knew what happens when people see the erotic as the only road to liberation. If you worship body too intensely you may end up in total attachment to it. If you cultivate only the beautiful, the alluring, and the desirable, what will you do when you and your partner grow old? Buddha had his own radical ideas regarding the flesh; he recommended meditation on age, death, and decay. The same idea appears in numerous Tantras, especially of the northern tradition. Here we encounter Tantrikas, Hindu and Buddhist, who made a point of seeking out sites of danger, horror, fear, revulsion, and pollution. Most prominent among these were cremation grounds. In orthodox Hinduism, corpses are among the most polluting objects conceivable. A strict Hindu may not touch corpses, and visits to cremation places require considerable re-purification. At this point it may be useful to understand that cremation places are not only sites where corpses are burned. Poor people often did not receive much of a funeral, corpses were not always thoroughly incinerated, and in some famous cremation grounds, burial is common. Kinsley (1998:153) mentions the famous Tarapith in Bengal, where up to 60% of the corpses are buried. The regular addition of new corpses shifts elder ones, and consequently it is an easy matter to acquire skulls and bones. Several resident ascetics collect skulls which they use for begging bowls, ritual decoration, or for the erection of the classic corpse-seats. Such a seat may be freshly arranged, but it can also be made by burying a number of skulls in the earth floor of a hut or ritual space. Traditionally, under the seat should be the skulls of a Sudra, Jackal, tiger, snake, and a kumara (virgin girl). These five skulls form the seat of the adept, they constitute a focus of power and a link to the other world. Then there is corpse-sitting, another topic you’ll never hear about in a ‘Tantric Workshop’. It features prominently in the rites of Kali, Tara, Bhairavi, and is often associated with the Mahavidyas. Usually, corpse sitting was part of the basic initiation; sometimes it was practiced for specific rites of sorcery to gain special powers or to attain liberation. Some worshippers were initiated on a corpse at night. Traditionally, Tantric adepts used fresh corpses - usually those of low class men and women who had died suddenly, be it from suicide, poison, snakebite, accident, drowning, murder, or killed on the battlefield. Corpses of immoral, famous, starved, or diseased people were not recommended. Nor those of the upper classes, if only because their relations kept them guarded at night. In general, the corpse was specially laid out, decorated, identified with a deity, and worshipped. Incidentally, such worship was thought to benefit the soul of the deceased. At some point the corpse was laid on its belly. A yantra was drawn on the back, a mat placed on top, and the worshiper straddled the corpse much like riding a horse. During the night the initiate worshiped the corpse, and the deity within it (often Shiva), recited mantra, did pranayama, and made offerings. At some point, the corpse moved, made weird sounds, or even began to speak. You have to be pretty spaced out to get this effect. Others placed a board on the corpse and sat on that. Then there are those who buried the corpse of an infant, baby, or fetus to sit on. Such rituals, revolting as they may seem, were not rare perversions of a spiritual tradition. They appear in earliest Tantric literature and for all I know they are still practiced secretly. Think deeply about the symbolism. The corpse, a thoroughly polluting thing, becomes a vehicle that carries its rider out of acceptable social reality and conditioning. It destroys all class-connections. A Hindu who touches a corpse loses class and literally drops out of the social and divine order. Moreover, the freedom enjoyed by the freshly initiated adept is based on acceptance and integration of death. While the rite may produce karmic benefits for the soul of the deceased, it certainly reminds the initiate of her or his own mortality. In a certain sense the corpse is not just a corpse. It is your own corpse. When you can sit on your own dead body you’ll understand what liberation is all about.
Starting with such rites, numerous Tantric adepts introduced emblems of death in their worship. Several schools of Tantric Buddhism use thighbone trumpets and bone ornaments for ritual. Yoginis, both Hindu and Buddhist, frequently wore aprons made of human bones. Skulls feature prominently in several Tantric systems of Bengal. They were often placed on altars or buried beneath them, just as they were buried underneath buildings and shrines. It might remind you of the skull worship in Celto-Germanic religions. Skulls could represent deities; they could also represent deceased worshipers. Some assembled skulls, painted bright red to represent energy, in their shrines as a source of power. Others accepted the skulls as students and taught them to achieve liberation, just as human disciples are educated. A guru gains power and merit by liberating others, no matter whether they are alive or dead. It was assumed that the souls that used to inhabit the skulls obtain blessing and karmic benefits in the process. For a vivid account of the use of skulls in Kali worship see June MacDaniel in White, 2000: 77, and her full presentation of the subject Offering Flowers, Feeding Skulls (2004). All of which may suggest that a well-organized Tantrika needs good connections to the Untouchables who collect and burn the dead. Finding corpses is not very difficult in a country where every new plague provides dead bodies at the roadside. The problem lies in collecting them. In old India, folks who handled the dead and the dying had an extremely unpopular place in society. Those who touched corpses in their worship did so as secretly as possible. The alternative to using real corpses is meditation. Numerous Tantric adepts repeatedly imagined their own death in trance states. They visualized their dying cramps, the final spasms, the release of excrement and urine, the cooling of the flesh. Many imagined how scavengers devour them, beasts like jackals, hyenas, raven and crows, all of them vehicles of the goddess. They imagined decay, purification and the final dissolution of all body. Then they rebuilt their body-vehicle from mantras, energies, colored lights, and returned to daily life full of enthusiasm."