Pre-ejaculate is the clear fluid that is released out of the penis prior to a man's ejaculation. It can often be seen or felt on the tip of a man's penis while he is sexually aroused and has an erection. Pre-ejaculate is released from the Cowper's gland, and it reduces the acidity of the urethra, making it a safer environment for the sperm that will be released later.
Pre-ejaculate is also known as pre-cum.