How can I get permission to use the Gatorade logo and slogan for school t-shirts?

Our high school student council would like to use the Gatorade lightning bolt logo and the "Is it in you?" slogan to make cl t-shirts. We would change the colors used in the logo, as well as changing the words in the logo. The slogan would remain unchanged. We would be selling these shirts as a fundraiser at our school, so I'm pretty sure we would have to permission since the logo and slogan are trademarked. Any information regarding how I could obtain permission to use trademarked materials would be greatly appreciated.