Tantra includes many different practices, but it is chiefly known as a means to enlightenment through identity with tantric deities. To observers the deities are best understood as archetypes representing aspects of enlightenment, although to the tantric practitioner the deities must become as "real" as himself.
The "Four Purities" provide an outline of basic tantra:
- Perceiving one's own body as the body of the deity
- Perceiving one's surroundings as the mandala of the deity
- Perceiving enjoyment and happiness as bliss of the deity, free from attachment
- Acting only for the benefit of others (bodhichitta)
Tantra is confusing to observers, because it looks like polytheism. However, it is not. It's enormously important for tantra to be approached within an understanding of shunyata, or it devolves into nothing but polytheistic god-worship. Within an understanding of shunyata, the deities are neither real nor not-real; they find existence in what they evoke within the practitioner.
In popular culture, tantra is associated with sexual practices. This may be because much of the imagery associated with tantra is highly sexual; copulating deities, for example. The actual sexual practices of religious tantra, however, are supposed to be free of lust and mostly involve visualizations.
Although tantra is associated with the Vajrayana practices of Tibetan Buddhism, there are elements of tantric practice in most schools of Mahayana Buddhism.