The one thing that everyone seems to want more of is sex. So once you've done the hard work of setting the scene, getting her in the mood and making sure you're wearing your best pants, why not make the actual event something to savour, rather than a time trial?
When she's on top, your penis is less stimulated. And ask her to go slowly – long and fast thrusting is hazardous to a man's endurance. You might also try entering your partner and not moving at all for a few minutes to acclimatise your penis to the feeling of her warm, wet insides.
The idea here is to have her stimulate you until you feel yourself nearing orgasm, and then ask her to stop. Once your sexual tension diminishes (in about 15 seconds), she can continue. It sometimes helps to put a number on the feeling, say, zero for no arousal and 10 representing ejaculation. This way, with practice, you'll be able to tell her you're at a six and can warn her to stop when nearing eight.
Fast shallow breathing correlates with ejaculation, so breathe slowly and deeply and you may be able to reduce the anxiety that's contributing to your hair trigger. Try breathing so that your belly rises before your chest does. Try it while practising start-stop and squeeze. A yoga-style breathing technique may help, too.
After she's sufficiently aroused through oral sex, ride the shaft of your penis through the lips of her vulva, stimulating her clitoris, but never entering her. Do this for a few minutes, then press the end of your penis into her clitoral head. Rub your glans against her clitoris. Linger in her vaginal entrance where the most sensitive nerve endings are.
When you do have intercourse, focus on small, shallow movements that penetrate the first 2 to 3 inches of her vagina. When you recognise yourself getting close to coming, pull away and regain your composure. Then enter her again. Switching positions may help also help you prolong sex.
The area of the brain responsible for triggering orgasm is engaged whether you're trying to have one or halt one. The more attention you give it, the more likely it is to arrive. Focus on what's happening now – her silky thighs on your hips, say – and you'll diffuse pleasure throughout your whole body.