Describe process of sexual intercourse

Man's penis becomes hard and erect to penetrate woman's vagina. Ejaculation(release of sperm) occurs due to contractions of the sperm ducts and other muscles. As the sperm pass along the sperm duct and urethra, they are mixed with a fluid from seminal vesicles and prostate gland to make a sticky fluid called semen. Semen is ejaculated from penis into vagina.