What I have found with my wife is that the key is your (the male) control over when you do. Not all guys can, but I can pretty much hold it back and hold it back until Im ready. That's the best advice I can give...learn to control when you do, and then just do it when she is.

Now, all this is assuming that she can have orgasms from vaginal penetration, which some women cant. If not, then you guys will have to find another method.

We've recently found that the CAT (coital alignment technique) can really work as well. I personally found that the internet guides available only give you some idea of whats needed, but if you keep trying then eventually it will click. When it does... wow.

My boyfriend and I cum together often, we know we are lucky as it is quite difficult to do. I find that lots of foreplay helps beforehand and doing such positions as doggy really help as it touches the G-spot. To stop him cumming quickly he thusts quickly for a few minutes then stops which stimulates me at the same time, by the time he wants to cum he is thusting so quickly it make me cum as well. There is no science I'm afraid just lots of practice, which is never a bad thing  

It happens. Rarely. With practice, you may come close once in a while.