Yes, this is a true story.
In a study titled “A Curious Case of Rectal Ejaculation,” published last month in the Cureus Journal of Medical Science, a team from the University of Texas Medical Branch at Galveston describe a patient who sought out treatment after five days of pain in his balls—and two years of “a substantial amount” of semen shooting out of his rectum.
When the 33-year-old man went in for a CT scan of his pelvis, doctors saw that he had a rectal-prostate fistula, a rare condition where the body develops a hole that connects the rectum with the lower urinary tract and creates all kinds of problems.
This patient had an extended hospital stay two years ago, just before his problems began, where he was placed in a medically-induced coma to recover from a cocaine and PCP overdose.
The researchers on this study hypothesize that an improperly-inserted catheter during his hospitalization could have caused the trauma to his urinary tract, and created the fistula.
His doctors were able to patch the hole with surgery and he made a full recovery.
Original study
https://www.cureus.com/articles/68327-a-curious-case-of-rectal-ejaculation