What Causes Thick Discharge From Penis Post Urination?

Greetings. For the first time today, I observed a clear jelly-like substance leaving my urethra after a normal urination. This was preceded by a bowel movement+urination combination, after which I stood up to zip my jeans. Before I could do so, I felt an urge to urinate, but the pressure felt somehow...different. I dropped trou, sat back down and dropped this jelly like substance from my penis. There is no pain, either in my urethra or prostate area.