Term used to define a fly shorty. Said shorty can't be spindly and thin, nor albino, and can't be a chickenhead either. To be Thick as a Snicker it helps if the girl is of color but it is not a requirement. Typically, the female will have an attractive posterior and legs and you'll be attracted to her instantly. This is also known as "having strong feelings towards the girl."
Term made popular by the Brandon Flowers (cornerback for KC Chiefs) tweet to random girl he saw on the street.
Me: Yo dude check out the bangin' chick going into that korean nail salon!
JP: Word up homes, she so fly that she Thick as a Snicker.
Me: Girl let me holla at you, I'm boning up seeing how you as thick as a snicker.
Girl: That's the best pick up line I ever heard! I'm glad you like my fly ass! Do you wanna come over later?
Brandon Flowers (via twitter): So to the light skin girl wit long hair that walked out of city hall around 5 that was thick as a snicker I have strong feelins toward u