This is a bit hard to describe. For me the key was to lean further back, while pulling up, until I almost fall back. Ass should be low, and elbows should be straight. Then it's a dynamic move upwards. Do not try to push the bike forward, instead pull straight up, and extend your body up until your stomach is touching the bars or stem. The natural inclination is to force the bike up, but it will really do it with very little input, just a hop. It's all about body movement, not bike manipulation. The bike will continue moving forward and up at the same time. It helps to think of pointing your toes when you hop, makes your legs get into a nice position to land. The most important part is to GO FOR IT! Plenty of speed, and really really hop, the bike will stay with you. A curb was never quite tall enough to work this out for me, but 2 pallets worked well. P>S> This technique is where I learned the importance of keeping a good grind on my rim, it's easy to land on your head once you can get up to rear.