Himitsu 秘密 Do you really want to know? ;-)
Longevity, immortality Is part of QiGong; Lasts years, needs meditation and has an enormous health effect... Long reading work... But is increasingly underpinned by research results... David Andrew Sinclair Greenland shark
Tantra, Daoist/Hinduist/Buddhist Is part of QiGong; Lasts years, necessarily meditation, long reading work... First get to know a few years of body spirit and consciousness in meditation practice; otherwise the monkey spirit will run away with you ;-)
Karezza, Tantra, Daoist Bedpractise Is part of QiGong; Lasts years, is a practice, requires meditation and has enormous health effects... But very secret, intimate and taboo topic. Body perception, friendly attentive and calm :-) View Beforehand have look at Aufklärung Verein Lilli. There is already a large part of what It's all about; unspectacularly.