Possibly a reference to Swizz Beatz' multi racial background. The girl asks him about his ethnicity. His response is intended to shut her up.

(Swizz Beatz: not vanilla)
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Quoted by Yeezy in [Kanye West’s “Good Life”]http://rapgenius.com/Kanye-west-good-life-lyrics
A reference to both the movie and book ‘Lolita’. Similar to the novel’s protagonist, Lana wants what she knows she shouldn’t, in this case, the diet mountain dew character.