C*m..

But when does precum turn into like c*m c*m.. like when a guy first goes then that is precum and then what.. like 5min its like the general c*m??

Don't think of precum as 'the big bang'
It's kind of like when afemale gets aroused and becomes wet.
its actually a clear substancevery much like semen but... sperm often remains in the uretha fromearlier ejaculations (last night, today... can survive for about 3 daysin some circumstances)

Precum doesn't -turn into- ejaculate. they are different.

Here are some Wikipedia articles excerpts:

PRECUM-
The fluid is usually secreted by Cowper's glands during foreplay or at an early stage during sex, some time before the man reaches org**m and semen is ejaculated. Pre-ejaculatory fluid prepares the urethra for the passage of semen and neutralizes acidity due to any residual urine. It also lubricates the movement of the foreskin over the glans. The amount of fluid that the human male can issue varies widely between individuals, from imperceptible amounts to a copious flow.

A problem for couples who seek to avoid pregnancy, however, is that the pre-ejaculate may contain sperm. This is one additional reason why withdrawal (coitus interruptus) is not considered to be a reliable method of birth control. There have been no large-scale studies of sperm in pre-ejaculate, but some smaller-scale studies suggest that any sperm present may be ineffectual at causing pregnancy.[1] It is commonly held, but as yet unverified, that pre-ejaculate may pick up existing sperm in the urethra if the man has not urinated since his last ejaculation.

C*M C*M-
During emission, the two ducts known as vas deferens contract to propel sperm from the epididymis (where it was stored) up to the ampullas at the top end of the vas deferens. The beginning of emission is typically experienced as a 'point of no return'. The sperm then passes through the ejaculatory ducts and is mixed with fluids from the seminal vesicles, the prostate, and the bulbourethral glands to form the semen or ejaculate. During ejaculation proper, the semen is ejected through the urethra with rhythmical contractions.