Generalities:

Premature ejaculation is a disorder that involves the premature and involuntary expulsion of semen shortly after having started intercourse.
For a short time you can refer to a few minutes. Above all, the essential thing is that the disorder can cause frustration in the man and his partner..

There are many factors that may be involved, including psycho-emotional factors, prejudice, guilt, shame, etc. Review the psychoemotional pairs, especially the pair pineal - prostate.

Several physiological factors could also play an important role such as having diabetes, dyslipidemia or infection, various infections that may affect the genital area or hormonal balance, such as the pair of yersinia pestis. 
Finally, you should also analyze various habits and lifestyle such as smoking, alcoholism, use of drugs, promiscuity, among others.

Going to psychoemotional and /or sexual therapy can be of great help.