Long time no sex life semen redness may be strenuous masturbation or ejaculation when holding back, resulting in urethral mucosal damage caused by, but also may be the seminal vesiculitis, prostate cancer and other diseases lead to. Long time no sex life, if in the masturbation is more violent or masturbation time is too long, in the ejaculation time hold not ejaculation, it is easy to appear urethral mucosal damage, resulting in mucosal bleeding, can be mixed with semen to form blood semen. If there is seminal vesiculitis, the mucous membrane of the seminal vesicles will be congested and edematous, and the semen will impact the mucous membrane of the seminal vesicles to bleed during ejaculation, thus causing hematospermia. In patients with prostate cancer, since the seminal vesicles are close to the prostate gland, the invasion of prostate cancer into the seminal vesicles can easily cause hematospermia. If you exclude the urethral mucosa damage, you need to go to the hospital for further consultation, do seminal vesicle ultrasound, seminal vesicle magnetic resonance and other related examinations to exclude inflammation or tumor of seminal vesicles.