The bulbourethral glands are part of the male reproductive system. They may also be referred to as the Cowper's glands since they were first documented by anatomist William Cowper in the late 1600s.
The paired bulbourethral glands are roughly the size of a pea and are located in the deep perineal pouch. They are at the base of the penis and are lateral (to the side) and posterior to (behind) the urethra, which is the tube through which semen and urine exit the body.
They are exocrine glands with approximately 2.5 cm ducts that pass through the perineal membrane and into the nearby portion of the spongy urethra. When sexually aroused, the glands produce a mucous-like fluid called pre-ejaculate. The pre-ejaculate fluid is a viscous, clear, and salty liquid that neutralizes any residual acidity in the urethra. The now neutralized urethra is a more hospitable (as opposed to harmful) environment for the sperm to travel in.