Kegels are important because they strengthen the muscles responsible for keeping maximum blood to the penis. As you grow you will need more blood in your penis and without exercising these muscles you may end up with a bigger penis that can not get 100% erect. Reverse Kegels are used in stretches because they unflex these same muscles allowing you to stretch the penis without interference from these muscles. A reverse kegel allows 100% of the stretch to go to the penis, instead of the muscles.