Fresh air feeding the crankcase ventilation system enters at the front valve cover via a hose that comes from the throttle body, fed via a port before the throttle plate. Vapors are extracted via a hose fitting in the crankcase valley that returns to the bottom of the throttle body. There are three outlet ports for the extracted air/crankcase mixture in the throttle body. Under various throttle positions, the air and crankcase gas mixture flows differently through these outlet ports.
After a long idle, if it smokes when you first get on it but then clears if you keep pushing, or if it clears after repeated back to back passes, that points to a valve seal. If it smokes badly all the way through the run, or if it gets worse the harder you push, then that suggests a problem with an oil control ring.