Hi and thanks for the query, This is a common phenomenon and is described by most men. Urination after sexual intercourse is common practice and is but normal, but associated pain should be evaluated. Sustained penile erection before penetration could be associated with this syndrome at times. The most frequent cause of this however could be a urogenital tract infection and is also seen in a chronic infection of the prostate gland called prostatitis. In a small number of patients, even after a detailed assessment, no identifiable cause is actually identified. Urogenital fistulas and nerve compressions could be at the cause too. I suggest you book an appointment with a urologist for a proper evaluation. Thanks and best regards, Luchuo, MD.