Natural curly hair for black people?

I'm a African American with natural hair. I don't have any chemicals in it and I do t want any. My hair is so many different textures. It's pouffy and curls little in the front , in the back it's so nice and curly. And on my lower sides, it's straight!! I buy curl products for my hair and it works, but my hair Poofs out Cause it air dries ! Do you think I can diffuse my hair to make it stay curly, or do you have any other techniques for me to keep my hair nice and curly? :) btw I think my hair is naturally straight