Hello, Blood squirts on full erection can be indicative of some trauma, injury or tear due to rough or aggressive sexual intercourse. STD and UTI are other common factor that cause blood in semen or urine. Medical conditions like kidney stones / infection, bladder infection/cancer, prostate cancer, etc., can also cause similar symptoms. You are advised to get clinically examined by a urologist and get urinalysis (R/E and C/S) to detect if blood is in the urine or semen. You will be examined to detect any injury, tear or trauma that is causing bleeding during erection. You will be treated accordingly. Get STD tests done, if reports are positive, you will be treated with antibiotics and antivirals. Get required blood tests, imaging tests, etc., to detect underlying medical conditions that are causing you symptoms. Your treatment will depend on the medical condition detected. Avoid sexual intercourse or any type of sexual activity for a couple of days. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician