Right side sun
Video (1404kb)
This one is the 'standard' sun. The diabolos move upwards between the hands. That means there are no twists involved, so you can keep it going while the diabolos have enough spin, then exit straight to the shuffle.
If you watch the video, you'll see that I turn to face the diabolos. It's possible to do this sun without turning, but it's easier to turn with it while you're learning. To get the push, I lift the shuffle out to the right to get a little pause in the shuffle. Look for the moment where both diabolos pause slightly, both at the same height above the ground. That's the moment you need to do the sun.
Give the rightmost diabolo a push downwards, as if you're doing a one diabolo sun. When I was learning this trick, I found that it worked better the more I practiced the same trick with one diabolo. If you get the push right, both diabolos will travel between your hands and right over the top. There's no secret to it beyond that, I think you'll get it just by working at it.
You might find that the second diabolo drops too early. You need to push it over the top using your left hand, after the first diabolo has passed between your hands (but still while doing all this as one smooth movement!).
This video (3.3mb) shows me doing continuous right side suns. Once the sun has started, it's fairly easy to keep it going, so once you can do one sun, you should try to keep it going. If that works, you're ready to learn about linking different suns together.