Genetics plays a major role in determining penis size, and there is no safe or proven technique to permanently grow it using drugs, oils, or exercises, many marketed items are dangerous or unsuccessful. Maintaining a healthy weight, exercising frequently, and having adequate blood flow can enhance the quality of an erection and make it appear fuller without really increasing its size. A doctor can effectively cure issues like erectile dysfunction if you're worried about your performance, so it's better to get the right medical counsel rather than attempting untested treatments.