Hello, Rectal bleeding may not be associated with masturbation. However, excessive or vigorous masturbation may trigger the neuronal supply of anus as the same nerves supply the penis. So, if you have anal fissure, fistula or hemorrhoids you may experience pain and bleeding. You are suggested to get clinically examined by a urologist / GP. There are other medical conditions that may cause similar symptoms like ulcers, polyps, IBS, diverticulitis, etc. Get blood workouts, Urinalysis, Stool tests, Imaging (X-RAY / CT / MRI) done to detect the cause, get treated at the earliest. If sexually active your treating doctor will tell you to do STD tests. You will be treated according to the symptoms detected. To get relieve from pain you can take PPI s and Acetaminophen, one SOS when needed. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician