Hi. I am a 25 year old male. As far as I would recall, the last 4 times that I masturbate in the last 5 to 7 days, I saw tiny little blood vessels in my sperm, approximately 1mm to 1.5mm was the length. I know it is not just blood because it did not stain the tissue. I remember most of the time, it came out only in the first ejeculation, not any in the consequent ejeculations.