Answer:
It's main function is to produce and release the "pre-cum" to rid the urethra of any acidic urine. The clear fluid neutralizes urine in the urethra so that when a man ejaculates, the sperm in the semen are not destroyed by acidic urine leftover in the urethra. The whole purpose of ejaculation is to send healthy sperm out of the male and into the female reproductive system for fertilization; this can't happen if the sperm come into contact with acidic fluids.