A larger corpora cavernosa results in a larger and more erect penis. The corpora cavernosa is made up of two tubes that run along the entire shaft of the penis. The corpora cavernosa expands to accommodate the blood that rushes into it when you become sexually aroused. It stretches like a balloon to make your penis extend and become erect and rigid. The more blood that goes into this area, the larger and harder the erection you achieve will be.
Perform Kegel exercises. According to Seekwellness.com, Kegel exercises work your pubococcygeus muscle, or PC muscles, the hammock-like set of muscles that extends from the pubic bone to the tail bone and is responsible for maintaining the blood flow to your penis, as well as keeping that blood in your penis. The way to identify this muscle is urinate and stop midstream; the muscle you use to do this is your PC muscle. Strong PC muscles will allow you to keep the largest amount of blood in your corpora cavernosa during an erection. This will not only help you maintain your erection, but also keep it at its absolute hardest and fullest without losing rigidity. Clench and release your PC muscles for a count of 10 for 3 to 4 sets.
Buy a penis ring. According to Columbia University column, GoAskAlice.com, a penis ring helps trap even more blood within the penis by assisting what is call the tunica, a sheath that encompasses the corpora cavernosa . The tunica is responsible for allowing blood to leave the corpora cavernosa. Use a ring to limit the ability of the tunica to take blood away from the corpora cavernosa. Achieve a slight erection and then insert your penis through the ring; it should fit snugly at the base of your shaft. Forcefully contract your PC muscle to draw blood into your penis. With the ring in place, you can trap more blood in the corpora cavernosa and make it fuller, giving you larger erection.
Jelq. Jelquing is done by creating an "OK" gesture with your fingers and performing a milking motion from the base of your penis to the beginning of the head of the penis. The premise of this exercise is that the motion will allow more blood in and expand your corpora cavernosa. As it grows in size, your penis will become larger. This method is not backed by any definitive research, but is popular and, according to Pegym.com, was an ancient Arabic method of enlarging the corpora cavernosa.