Ejaculating quickly during masturbation does not necessarily mean that you have premature ejaculation, as this condition is usually assessed in the context of sexual activity with a partner and control over timing. Concerns about genital size are very common, and in most cases, the size is within the normal range, and there is no medication to increase genital size. You may benefit from behavioural techniques such as the start-stop method, pelvic floor exercises, and relaxation strategies to improve control. If the concern persists or causes distress, a doctor can assess you and prescribe appropriate treatment if premature ejaculation is diagnosed.