Tibetan Buddhists Believe You Need to Have Sex to Become Enlightened
Lama Thubten Yeshe (Introduction to Tantra, 147) wrote:
"There is a certain point in the mastery of the completion stage where physically embracing a consort is necessary . . . ."
Je Tsong Khapa who founded the Gelugpas, agreed that to attain Buddha-hood in one lifetime, it is necessary to use an actual consort (karma mudra) saying,
"A female companion is the basis of accomplishment of liberation."
That is, in order to generate an illusory body as that of a particular deity with all the qualities of existence, another person must interact with it.
Tsongkhapa, founder of the Tibetan Gelugpa sect is of the same opinion:
“A female companion is the basis of the accomplishment of liberation” Shaw, 1994, p. 146 Shaw, Miranda, Passionate Enlightenment: Women in Tantric Buddhism, Princeton 1994.
The Dalai Lama said he would not reach enlightenment in this lifetime because he did not have a consort.
The Dalai Lama also said that many within Buddhist schools believe that the Shakyamuni became enlightenment with a consort under the Bodhi Tree and that his was edited out in many iconographies and written accounts.
It is generally understood in the tantric tradition, that it is not possible to bring all five winds into the central channel at the same time unless one performs karmamudra. The yogi will do the practice at an advanced stage. Milarepa did karmamudra with dakinis. The source for the oral instructions on the completion stage of the Kalachakra Tantra by Geshe Ngawang Dhargyey of the Gelugpa. I've also heard this from the Drikung Kagyu lamas. In some lineages an advanced yogi who is a monk will take a consort and it is not seen as violating vows, because this is what the Buddha said to do as part of the tantric method.
In Dzogchen and essence mahamudra, karmamudra is not important, and works with different channels.
From The Essential Dalai Lama: His Important Teachings by Dalai Lama:
"Yogis who have achieved a high level of the path and are fully qualified can engage in sexual activity, and a monastic with this ability can maintain all the precepts."
From the book: Dreaming the Great Brahmin: Tibetan Traditions of the Buddhist Poet-Saint Sarah
for those unaware of the nature of everything,
Great bliss is attained in sexual union;
As if thirst-ridden, chasing after water in mirage,
They die from thirst, and do they ever drink the sky-water?
Whoever frolics in this bliss,
Living between vajra and lotus,
What for? This has no capacity for truth,
So {where} in the three worlds will you be complete?
The bliss of means is the moment,
And this itself becomes both;
Through the kindness of the master,
A handful in a hundred will understand.
from:
http://downthecrookedpath-meditation-gurus.blogspot.com/2011/09/tibetan-buddhists-believe-you-need-to.html