The epididymis is a coiled tube located at the back of each testis. It plays a crucial role in the male reproductive system by storing and maturing sperm cells produced in the testes. The epididymis allows sperm to gain the ability to swim and fertilize an egg. Sperm travel from the testes to the epididymis, where they can remain for several weeks. Once mature, sperm are transported through the vas deferens during ejaculation. The epididymis is essential for ensuring that sperm are fully developed and capable of successful fertilization.