Pre-come is clear white fluid that comes out of the penis when a guy gets excited.
This happens before the guy comes to orgasm and ejaculates.
Pre-come serves as a lubricant and it cleans the urethra before the semen comes out, neutralizing the acid of the urine.
It can be just one drop, but also a large amount.
Pre-come might contain sperm cells! So as soon as you enter a vagina you have to use condoms. The withdrawal method is not a safe method to prevent unwanted pregnancy. With your per-come you may father a child.
Never trust a guy if he tells you he will be careful. He has no control over his pre-come (and many guys have no control over their orgasm). So if you don’t want to become pregnant always (!!!) use birth control when you have intercourse.