on a technical note get as low as you can, in essence stumble, and at the same time dive forward. Use your free hand to brace the impact and then get you gun hand with palm up so barrel faces up (trust, it does work) and then the rest of your body...
so it's run, get low, stumble and dive, free hand down first, then gun hand, palm facing upwards and then the rest of your body.
Like the other guys say just do it and don't think about it in a game....when your not playing or having anything to do with paintball, rehearse it in your mind and it'll come. worked for me...
btw get elbow/forearm pads as they help protect your arms....