Sun channel breathing involves inhaling through the right nostril, which accesses the energy channel that runs up the right side of the spine—the tawny current (pingala nadi). The practice is warming and energizing.
To try it, sit in a comfortable cross-legged position and take a few easy breaths. Then close your left nostril with your fingers and inhale through your right. At the end of the inhalation, close your right nostril so both nostrils are momentarily closed. Then release your left nostril and exhale through the left. At the end of the exhalation, close your left nostril so that both nostrils are momentarily closed. Then release your right nostril and inhale through the right.