Urethritis refers to inflammation, pain, and burning in the urethra before, during, or after urination. In men, this is commonly felt as pain in the penis, as the urethra runs on the underside of the penis. Urethritis is most often caused by an infection. Bacterial infections are most common, but viral urethritis can also occur.
https://www.newyorkurologyspecialists.com/uti/urethritis/men/uti-after-oral-sex/