Some ways to postpone your orgasm:
1.      The squeeze technique.
2.      The stop/start method.
3.      The scrotal tug.
4.      Clenching or releasing your PC-muscles. Every guy is different, so you have to find out what works with you.
5.      Proper breathing can help. Taking a few deep breaths will make you more relaxed and calm the arousal and tension that lead to rapid ejaculations.
6.      You can use a special condom: Durex Performa. It contains a cream which makes the penis temporarily less sensitive, thus postponing orgasm.
7.      If all else fails a doctor can prescribe an anti-depressant. But you have to consider the pros and cons. It might help to postpone orgasm for a few minutes, but it also might have many disadvantages.

See also: the finger lock