Tony Buzan in his book Make the Most of Your Mind relates the story of an Indian Yogi, Swami Rama, who in a lab experiment was able to willfully change the temperature of a spot on his right hand. What specific yogic/tantra practice would help do this feat? Here is the relevant excerpt from this book:
Then in March 1970, an Indian yogi, Swami Rama, visited the Menninger Foundation in Topeka, Kansas, where researchers were doing some exploratory work in the field of one of mankind's fondest dreams: the control of the body with the mind. In a series of experiments, Swami Rama was wired for brain waves, respiration, skin potential, skin resistance, heart behavior, blood flow in the hands, and temperature. While he was thus "wired up" he caused two areas a couple of inches apart on his right hand to change temperature in opposite directions. The rate of the temperature change was about 4° Fahrenheit per minute, and he was able to maintain the change until there was a temperature difference of 10°.
Swami Rama also demonstrated that he could "stop his heart" from pumping blood around his body. It was assumed by the researchers, Alyce Green, Thelma Green, and Dale Walters, that his heart would actually stop beating. What happened instead was that his heart began to fire at about three hundred beats a minute, without blood either filling the chambers properly or the valves working properly.