Thompson, John (2014). "Buddhism's Vajrayāna: Meditation". In Leeming, David A. (ed.). Encyclopedia of Psychology and Religion (2nded.). Boston: Springer. pp.250–255. doi: 10.1007/978-1-4614-6086-2_9251. ISBN 978-1-4614-6087-9. Some traditions are related to Vajrayana, but are not to be seen as "Vajrayana" or "Mantrayana" proper. Vajrayana here referring to the Buddhist tradition based on the tantric literature of North Indian Mahayana, the Buddhist tantras and the works of the Nalanda - Vikramashila masters and the Buddhist mahasiddhas. However, these related traditions may have been influenced by Vajrayana proper and have borrowed practices from Vajrayana schools.

Southern Esoteric Buddhism" or Borān kammaṭṭhāna ('ancient practices') is a term for esoteric forms of Buddhism from Southeast Asia, where Theravada Buddhism is dominant. The monks of the Sri Lankan, Abhayagiri vihara once practiced forms of tantra which were popular in the island. [128] Another tradition of this type was Ari Buddhism, which was common in Burma. The Tantric Buddhist 'Yogāvacara' tradition was a major Buddhist tradition in Cambodia, Laos and Thailand well into the modern era. [129]Garson, Nathaniel DeWitt; Penetrating the Secret Essence Tantra: Context and Philosophy in the Mahayoga System of rNying-ma Tantra, 2004, p. 45 This practice [of sexual union with a consort] is not taught for the sake of enjoyment, but for the examination of one's own thought, whether the mind is steady or waving. [61] Davidson adds that Buddhists and Kapalikas as well as other ascetics (possibly Pasupatas) mingled and discussed their paths at various pilgrimage places and that there were conversions between the different groups. Thus he concludes:

Vietnamese Buddhist esotericism is known as Mật giáo or Mật Tông and is a common part of Vietnamese Mahayana Buddhism (along with Pure Land practice and Thien). [113] Commonly recited esoteric texts include Uṣṇīṣavijayadhāraṇī, the Nīlakaṇṭha Dhāraṇī and the Śūraṅgama mantra. According to Quang Minh Thich "at present, it is still the norm in Vietnamese Buddhist temples, both in Vietnam and abroad, that these mantras, as elements of the Mantrayana, are recited either in their distinctive chanted sessions or in conjunction with other popular Buddhist scriptures. In function, the Vietnamese Tantric practices serve as a complement to the practices of Zen and Pure Land, not as an independent tradition." [113] Trungpa, Chögyam and Chödzin, Sherab (1992) The Lion's Roar: An Introduction to Tantra ISBN 0-87773-654-5 p. 144. This dissolution into emptiness is then followed by the visualization of the deity and re-emergence of the yogi as the deity. During the process of deity visualization, the deity is to be imaged as not solid or tangible, as "empty yet apparent", with the character of a mirage or a rainbow. [74] This visualization is to be combined with "divine pride", which is "the thought that one is oneself the deity being visualized." [75] Divine pride is different from common pride because it is based on compassion for others and on an understanding of emptiness. [76] A Tibetan depiction of the perfection stage practices of tummo (Skt. candali, inner heat) and phowa (transference of consciousness) Snellgrove, David. (1987) Indo-Tibetan Buddhism: Indian Buddhists and their Tibetan successors. pp 168.Kongtrul, Jamgon; Barron, Richard (1998). Buddhist Ethics. The Treasury of Knowledge (book 5). Ithaca: Snow Lion. pp.215–306. ISBN 978-1-55939-191-7. Vajrayāna practices are connected to specific lineages in Buddhism, through the teachings of lineage holders. Others might generally refer to these texts as the Buddhist Tantras. [1] It includes practices that make use of mantras, dharanis, mudras, mandalas and the visualization of deities and Buddhas. According to Vajrayāna scriptures, the term Vajrayāna refers to one of three vehicles or routes to enlightenment, the other two being the Śrāvakayāna (also known pejoratively as the Hīnayāna) and Mahāyāna (a.k.a. Pāramitāyāna).

If you go ahead and read Wikipedia and many other online and written sources they will describe Tantra as meaning ‘to weave.’ They will then go on to use the loom analogy, and imply this meaning is because of the way the Tantrik spiritual practice can weave across your day and life etc. The practice of ingestion of sexual fluids is mentioned by numerous tantric commentators, sometimes euphemistically referring to the penis as the "vajra" and the vagina as the "lotus". The Cakrasamvara Tantra commentator Kambala, writing about this practice, states:According to several Buddhist tantras as well as traditional Tibetan Buddhist sources, the tantras and the Vajrayana was taught by the Buddha Shakyamuni, but only to some individuals. [35] [36] There are several stories and versions of how the tantras were disseminated. The Jñana Tilaka Tantra, for example, has the Buddha state that the tantras will be explained by the bodhisattva Vajrapani. [35] One of the most famous legends is that of king Indrabhuti (also known as King Ja) of Oddiyana (a figure related to Vajrapani, in some cases said to be an emanation of him). [35] In Chinese Mantrayana ( Zhenyan), and Japanese Shingon, the most influential esoteric texts are the Mahavairocana Tantra and the Vajraśekhara Sūtra. [92] [93] Bahir, Cody R. Replanting the Bodhi Tree: Buddhist Sectarianism and Zhenyan Revivalism. Pacific World: Third Series Number 20 (2018): 95-129.