With retrograde Ejaculation, the semen exits backwards into the bladder & then is expelled the next tine you urinate. So I think it may require a medical procedure to extract semen. Why do you need a semen sample? Are you trying to determine if your semen is viable, or do you possibly want to use it for in-vitro fertilization to have a baby? If so, that can be done, but again, I think semen would need to be medically extracted for that purpose...