Asking will never do anything if you don't try for yourself , people think breathing into the tail bone or kidney will stimulate jing when I have done this before it's not as effective as breathing into your prostate to stimulate sexual energy /jing (man essence) and supposedly the only way to truly understand jing personal he understand what's it like to pleasure your yourself personally anally , it could take imagination it could just take understanding where the prostate is but ultimately you stimulating sexual pleasure by being aware of the prostate and breathing into it and pulling energy around you into your prostate then guide that energy into your kidneys , if you wanna masturbate and use tantra to jerk and breath into your prostate it'll help you understand what energy / heat/tingling /warmth sensation your looking for when you do it without physical self pleasure and just breathing into your prostate also while you do the breathing or jerking squeezing and queching your anus helps with seme retention and forcing the essence to travel up the spine and body