Diaphragmatic Breathing Exercises and the Vagus Nerve (2017)
Yoga (proper yoga, not the gymnastics they do in most gyms) is all about stimulating the vagus nerve and several others. The "locks" (bandhas) and various breathing exercises (pranayama) all work on it in different ways and stimulate different parts of the nerve. If you really want to juice it up add in some breath retention.Eventually you reach a sort of homeostatic state where your breath just naturally suspends, and that's when the doorway to the inner world opens.There's more about the nerves in The Accidental Yogi's ebook (free online), and more about breath retention in Kundalini Exposed (on Kindle). The "Supreme Kriya Fire" technique in that book is the absolute real deal, but definitely not for beginners. Beginners may want to start with Yogani's free lessons at aypsite.org.Remember - Kundalini is not a game. Work up slowly to avoid negative side effects.