The pills contain the PDE-5 class of inhibitors that increase the blood flow in the penis region. Hence, Cenforce 150 mg inhibits PDE5 which prevents the breaking of cGMP chemicals. They help in the relaxation of muscles and allow sufficient blood flow for a better erection. The penis remains erect for a long time until you reach the climax point. You need to be sexually excited to have a practical result of the drug on you.