There are many causes of rectal discharge chief ones being inflammation of rectum, infections, anorectal abscess
and fistula, polyps, cancers and ulcerative colitis. You need to get it examined from a doctor to confirm the diagnosis.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps.