TrueTantra.info writes:
Is Tantra about sex? Actually no! Out of the about 200 tantras that have survived to this day, only one (1) in passing mentions sex. So please understand this: What is called Tantra today and which mainly deals with sensuality, sex and extended orgasms has nothing to do with true Tantra.
Is that an accurate description of the tantras?
I can see why this question is not answered yet, because a prospective answerer must first determine: how many tantras actually exist? And surprisingly, this is not easily answerable: try to find a reference to the "about 200" figure offered in the question, or any figure at all, and you soon run into marginally scholarly publications by people citing numbers they heard from their guru.
T. Goudriaan states in "Hindu Tantric Literature in Sanskrit" (in his Hindu Tantric and Śākta Literature, Harrassowitz 1981):
[T]he accepted number of Tantras is sixty four. Our earliest authority for this figure is probably the [Vīṇāśikhatantra] which says that there were sixty-four “disciples in the Tantras.” Abhinavagupta points out that the Trika philosophy is the essence of the Lord’s teachings which are then divided over the series of ten, eighteen, and sixty-four texts. The “ten” are the Śaivāgamas: Kāmika etc. and the “eighteen” are the Rudrāgamas: Vitaya etc. These two groups together make up the “classic” series of Agamas: the Śaivāgamas are held to be dualistic, the Rudrāgamas to keep an intermediate position between monism and dualism, and the sixty-four “Bhairavagamas” are said to teach pure monism. The latter number thus became canonical for Tantric literature. When it comes to filling up this number with real titles, important differences can be noticed. … The list from the ŚrīkaNThī is neatly structured into eight groups of eight texts … we may assume … a tendency to fill out schemes with additional titles referring to deities. ... A late and apocryphal list of 192 Tantras ordered according to the threefold division into Krāntās is ascribed to the Mahāsiddhasāratantra.
I wrote a long passage about why I consider this bold skepticism to be justifiable, but on second thought, let's put that aside to look at the sex claim. Suffice to say we can guess that many texts have been lost but it's hard to confirm that in reality.
In the Kulacūdāmaṇi Tantra, one of the 64 catalogued, we find the following:
Naked, with betel leaf in his mouth, his hair [hanging] free, his senses under control, with eyes rolling from the effect of wine and in union with another woman, the [male] jewel of the clan should worship with aromatics and flower[s] the naked woman ...
(David Gordon White, Kiss of the Yogini: "Tantric Sex" in its South Asian Contexts, p. 88)
And from the Jayadrathayāmala, also one of the 64:
On the day sacred to the Lineage [of his Mother-goddess the sponsor] should celebrate a Vīramelāpa in a pleasant, secluded house that is free of all disturbances and full of the scent of flowers, fine incense, and fragrant powders. He should invite all those who maintain the observance of Bhairava, who know the discipline, are devoted to the Goddess, contented, intent on the Krama, Samayins, Putrakas, Sādhakas, Gurus, and Yoginīs, the last enlightened or, if such cannot be found, at least devout. ... . Some, personifying [A]ghora, eat vomit, and others *faeces [?]. Some will engage in copulation and drink its product when replete.
(Alexis Sanderson, “The Śaiva Exegesis of Kashmir.” In Mélanges tantriques à la mémoire d’Hélène Brunner, edited by Dominic Goodall and André Padoux, Institut français d'Indologie, 2007.)
It was exceedingly hard to find these texts in translation, but there you have it: two undeniably Tantric scriptures which mention sex in passing. Neither, I should caution, focus on sex. But there are plenty of books written by Indians before the 20th century and generally called "Tantric" which talk about sex in some detail, many of which are documented on the following sites:
The reason we can expect Tantric texts to talk about sex in detail is because they were secret initiatory texts specifically discussing transgressive acts (like eating vomit or feces). Generally the Tantras warn us not to use them as sex manuals, at the risk of death, etc. (source: Kiss of the Yogini and like every book about this)
