Ejaculation
First stage: Emission. The first stage is called emission (which means "the act of sending or throwing something out"). A man's testicles make sperm cells, and these are stored in a coiled tube called the epididymis. During emission, the two ducts (tubes) called the vasa deferentia (each tube by itself is called a vas deferens), which carry sperm away from the testicles, squeeze the sperm from the epididymis to the top end of the ducts. When this happens, the man feels that he cannot stop his ejaculation. It is sometimes said that the man has reached the "point of no return". The sperm then passes through other tubes called the ejaculatory ducts, where they are mixed with fluids made by glands called the seminal vesicles, the prostate and the bulbourethral glands (also called Cowper's glands). (Glands are special body organs that make chemicals.) The mixture of sperm and fluid is called semen or ejaculate. It is white or yellowish, and sticky.