Ok, I can teach anyone to do a backflip on a trampoline. This method has worked for many people - everyone who has tried. I assume you can jump up, land on your back, and spring back to your feet, right? Well here's what you do: start by standing, falling to your back like you're going to spring up, but instead of standing back up, roll backward to your feet. As you do this, add a flipping motion to it. Then start from jumping, to landing on your back, and "flipping" backward to your feet. This gets you the complete feeling of a backflip, without any danger of landing on your neck. After you get good at this, a backflip will come easily and feel like the most natural thing. Take it slow, and I'm sure you'll get it.