I just wanna know the difference.
Is it like one kind is in vagina the other is not? or what?
Cum usually has two parts - sperm and semen. The sperm has a single purpose - impregnation. The semen acts as a lubricant and a carrier for the sperm. Pre-cum is largely semen, but it usually carries tens of thousands of sperm with it. When orgasm hits, the ejaculate (or cum) is still both parts, but the sperm count now is in the millions.
bimjob is correct.
Pre-cum is something a guy produces when he is aroused. It's something that all men produce and cannot be controlled.
Cum is referred to when a guy ejaculates (orgasm)
precum comes randomly when the guy is excited lol. cum is the burst when there is an orgasm, but precum comes out all through sex in little bits.
so are you saying that you could get pregnant without a guy actually ejaculating within you while having sex?