A large number of men have a problem of ejaculating before the woman has an orgasm.
Fortunately, there are things you can do to stop this from happening...
Through a repeated series of stop and go you can make sure that you don't release your semen too fast.
This method, however, requires a lot of control.
You can also engage in Kegel exercises, which will give you more control over your PC muscles, which you can't control as your are ejaculating.
If you just started to have sex for the first time, premature ejaculation is normal.
Over time the excitement of sex will wear down and you will be able to last longer in bed.
It will also help if you have sex more frequently because if you are having sex once a week or so you are going to get very excited and lose control of yourself early on.
Men who ejaculate too soon are also likely to have high anxiety over their performance.
The more they think about ejaculating too soon, the more likely it is to happen.
Before you have sex, calm yourself down and imagine yourself doing fine.
The more calm you are the less likely things are to fall out of place.
If, during sex, your muscles are tense or you are holding your breath, you are increasing the chance of premature ejaculation.
Engage in sexual positions, other than the standard missionary position, which will allow you to be more calm.
For example, doggy style will take a lot of stress off of your muscles.
You can also practice your performance by masturbating.
Although most men try to get it off as soon as possible when they masturbate, try masturbating for 20 or so minutes before ejaculation.
This way, you can get used to the feeling of being aroused for a prolonged period of time.