The hardest Part is flying without dropping the shell. A needs to be pressed repeatedly while you hold B. If you let go of B, you lose the shell.
If you have a turbo controller, put A on turbo, leave BB's turbo off, and hold both buttons at the same time. Don't let go of either until you land on the platform.
Without Turbo, you should change the way you hold the controller. put your second finger in B and you middle finger on A. Hold B down, press A repeatedly. Resume normal controller position when you reach the top.
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Dennis, Nell, Edna, Leon, Nedra, Anita, Rolf, Nora, Alice, Carol, Leo, Jane, Reed, Dena, Dale, Basil, Rae, Penny, Lana, Dave, Denny, Lena, Ida, Bernadette, Ben, Ray, Lila, Nina, Jo, Ira, Mara, Sara, MARIO, Jan, Ina, Lily, Arne, Bette, Dan, Reba, Diane, Lynn, Ed, Eva, Dana, Lynne, Pearl, Isabel, Ada, Ned, Dee, Rena, Joel, Lora, Cecil, Aaron, Flora, Tina, Arden, Noel, and Ellen sinned. [Mario sinned!]