Tao Tantra, the branch of Tantra that evolved in China, considers that energy (Qi) flows through channels called meridians and energy centres called dantians (one below the navel, one at the level of the heart, one at the forehead). The energy flows via a circuit formed by the "Governing Channel" (red) that runs from the perineum up to the head, and the "Conception Channel" (blue) that runs from the head down to the perineum.
You can practice circulating sexual energy around the microcosmic orbit using visualization and breathing techniques.
Begin directing your energy up by visualizing a light moving up the spine while your exhale, and then down your front while you inhale. You can practice inhaling up and exhaling down and see what works better for you, but your energy should always move in a circle up your spine and down your front.
As you practice breathing up the spine and contracting your pelvic floor before an orgasm, you might feel orgasm energy rushing up your spine and exploding in your head. This is a called an energetic orgasm and can lead to a full-body orgasm.