When ejaculation during sexual intercourse occurs without any sense of voluntary control and within a minute or so of insertion of the penis, it may be termed rapid because the time available for sexual pleasure is quite limited for both people.
Although a few men tend to ejaculate rapidly as a response to anxiety or stress, most men who ejaculate rapidly have done so consistently from their earliest experiences with a partner.
Premature ejaculation is most often defined as ejaculating before both partners are ready,or having no control over when a man ejaculates.
Premature ejaculation is most often caused by anxiety or emotional stress of some sort like fear, anger, performance anxiety, or any other kind of emotional stress.
Premature ejaculation can most often been treated and totally cured. There are several treatments available. The most commons are desensitize creams, pills, and exercises.
Exercises will cure around 90% premature ejaculators and is most often considered the best cure.
For more reading you can visit Premature Ejaculation under control
Original text from the CDC public domain document at http://www.cdc.gov/nccdphp/drh/Africa_pdf/Chap_10.pdf
