Urethritis means inflammation of the urethra (the tube that carries urine from the bladder through the penis out of the body).  Symptoms of urethritis include discharge from the penis and pain or discomfort with urination.  The most common sexually transmitted infections to cause urethritis in men are gonorrhea and chlamydia.  When a man has symptoms of urethritis but has negative tests for gonorrhea and chlamydia, it is called NGU (non-gonoccocal urethritis) or NSU (non-specific urethritis).  NGU can be caused by infections such as chlaymdia, mycoplasma genitalium, herpes, adenovirus or trichomoniasis. You can get NGU from insertive anal, vaginal or oral sex (that is, putting your penis in someone else's butt, vagina, or mouth). It can be caused by an infection, and is sometimes non-infectious (that is, not caused by an organism like a bacteria, virus or parasite).