QUOTE(mantis @ Dec 15 2007, 05:59 PM)

have sex and don't ejaculate
Hmm - I think he's asking how you get yourself into a state that allows this.
I'd say
1) practice on your own
2) work a lot at PC muscle exercises
3) practice some kind of yoga/energy work
4) get your partner's support - she'll see the benefits ;-)
5) try using condoms, or thicker ones if you use them already
Through 1 & 2 you should be able to learn to have non-ejaculatory orgasms. They're almost as good as the normal kind, so this tends to reduce the attachment to ejaculation (and orgasm generally I think).
3, energy work, is important because you need to be aware of and fairly detached from, physical sensations to judge how close you are to the edge and respond appropriately. For this specific purpose, I think vinyasa/Ashtanga yoga works well. The PC muscle (aka mula bandha) is supposed to be engaged through the whole practice, the gymnastic nature of the vinyasa gives you some feedback about how well you're doing in this respect (your body feels lighter with the bandhas engaged) and you learn to monitor your breath to judge whether you're over-stretching or pushing yourself too hard. This last skill translates pretty well in a sexual context - and the stamina and flexibility are helpful too; it's easier to stay on track if you're not exhausted and physically comfortable and relaxed. (But if you do Ashtanga in particular, watch your knees - don't do the half lotus/lotus until your hips are flexible enough.)
Another benefit from energy work is that it can provide energetic sensations somewhat similar to orgasm (albeit generally much milder). If you're getting these sensations regularly during qigong or yoga, you probably won't feel such a need to get them during sex.
1-3 will also improve your stamina - in the sense of time to orgasm (ejaculatory or not). Women can only take so much - for some it's hours, limited by physical exhaustion, others seem to get a kind of overload of the nervous systems that makes it impossible for them to take further stimulation - sometimes after one orgasm. Regardless of your partner's limits, you can probably learn to outlast her - either with a long time to orgasm or ability to continue after the non-ejaculatory version.