Nineteen number naughty baby
Press it on your dial
The song is called 1991, so the number nineteen is definitely showing that off. Also it could mean that Azealia and her crew are young, which she states in the next few lines.
then next to that 1900 numbers are often business numbers, so when she says press it on your dial (call the number), she could reference to a sex-business / porn phone line.
basicly meaning she’s so sexy you wanna have phone sex with her.
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