The type of herpes that can cause bumps on the shaft of the penis and painful urination during an outbreak is most commonly caused by Herpes Simplex Virus Type 2 (HSV-2). This virus is known to primarily affect the genital area, leading to symptoms like sores or blisters on or around the genitals. If you are experiencing these symptoms, it's important to consult a healthcare provider for proper diagnosis and treatment options.