This technique originated centuries ago with the cannabis farmers of the Hindu Kush. They would split the stem (lengthwise) just above the soil and tap in a small piece of wood to keep the split open. It should be done at least a week before end of flowering and two is preferred. doing this will delay your harvest by 4-5 days.
However, what worked in the sunny high altitudes of the Hindu Kush in the 16th century might not necessarily work in your indoor closet at sea level using decent modern nutrients and a radically different strain of cannabis.