For example, in the book Tantric Quest by Daniel Odier, he traveled to a remote area to find his teacher, built a hut in which to live and listened to her teach him about the tattvas for weeks before he ever did his first exercise. His first exercise was to stand for three days with his bare feet on the edge of a cliff . I also highly recommend any and all books by Osho. Tantra is not about sex. Tantra is about how to live your life connected to the spiritual Source of all life.
Sex is only a small part of it, learned in advanced lessons, usually after many years of study.
In the US, many people want to proceed to advanced lessons in an hour. I aim for a middle ground in teaching. I do not call what I teach Tantra. That would be like saying I was a bishop when the Pope did not make me a bishop. I do teach many of the tantric techniques.