When pooping sperm comes out of my penis why?

This is quite common. It happens more frequently in some men than others. It's not abnormal. Abdominal pressure from straining and stool passing over the prostate and seminal vesicles (where semen is stored) can squeeze out semen and prostate fluid. If no pain or other symptoms, this is nothing to worry about.

It is probably not sperm but some prostatic secretion (if slimy) and not to worry about. Avoid straining to 'poop' If not better after awhile see Urologist