(Must be sitting down in order for it to work properly)
After a hard days work or just the usual male doings, when the chode is humid and sweaty, he scoots to the edge of the chair or wherever he's sitting and finds a comfortable position. He then must spread his legs and move them inward and outward (moving knees towards each other), creating a breeze with his thighs. In turn, the air makes the swampy conditions of his grundle cool in temperature.
On a hot day, when sweat has accumulated down your ass crack, you drop your pants slightly and have someone blow air straight down your cheeks causing an evaporative cooler effect resulting an immediate drop in body temperature.