The exhale is relaxed with no control at all. If the inhale comes via the nose then the exit should exit the nose. If you inhale through the mouth then the exhale must travel out the mouth. Exhale and inahle need not be the same duration. In short don't stop at the top of the breath or the bottom.
Breathing is one continuous loop.
Circular breathing balances the body's subtle energy system and breeds acceptance and emotional integration. Next do the six point touch and hold series. This touch and hold series is utilized to add energy to the meridians, speed the process, and access unconscious processes. Hold your fingers there for the duration of two circular breaths. Hold your bunched fingers on this point for two complete circular breaths.