Epididymitis is a term that we use to describe an infection of the epididymis. The epididymis is a portion of the testes the carry sperm from the testicle to the vas deferens. Infections of the epididymis can occur from a variety of different reasons. I suggest that you start by scheduling an appointment with your primary care physician
. Unless this infection was associated with a sexual transmitted infection such as gonorrhea or chlamydia, it is not likely to be transmittable. Thus the first step answering your question is for you to go get tested for gonorrhea and chlamydia and to be treated if you're positive. In terms of performing oral sex, there should not be any risk of you transmitting an infection from your testicle through your mouth. These two parts the body are too far apart for there to be transmission of the infection from one place to another. The risk of transmission through vaginal sex as stated above has more to do with the type of bacteria than anything else. If this is a standard bacteria and not gonorrhea or chlamydia, you simply need to be treated with antibiotics and it will get better. In any event, it is typically not transmittable from you to your girlfriend. Again, I suggest that you start by scheduling an appointment with your primary care physician. You can get tested for gonorrhea and chlamydia and make sure that you get treated for your epididymitis. You do not want to let this infection go.