Spoonful of Sugar- This one is easy.
Have a friend help you. Rachel Vs. Rachel, you have to high jump, double jump, then hit Up and B Button. Have your friend then use all four of his Silpheed gauge upwards immediately. As you are floating down, he should fall to the ground. Right before you touch the ground, use one Upwards Silpheed. Repeat this while your friend stays on the ground. By the time you are done with the fourth Silpheed, your friend should have all of his back. Have him use all of his upward again, and the achievement will unlock once you hit the ground.