Rosie the Riveter was a propaganda symbol of women who were working in factories during World War II while their sons were dying at war — Lupe is comparing these women to moms in the ghetto, while suggesting that his own rhymes are “riveting,” i.e. highly compelling.
“Pockets full of posies” references the nursery rhyme Ring a Ring o'Roses, which is widely (though mistakenly) thought to comment on England’s 1665 plague, i.e. the Black Death. If Lupe intended this it would be appropriate, as this set of lines refers to “black death” in the ghetto, and its effect on the families left behind.
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The most likely interpretation, given the context, is that Lupe is mispronouncing the word “menstrual” to fit in with the next bar; his windshield is so covered in chicken and/or deer blood that it looks like… well, you know
He may also be saying “minstrel”: his windows are tinted, like the black face of a performer at minstrel shows (popular in the antebellum and post-Civil War South, involving whites dressing up as black caricatures). On a deeper level, Lupe may also be suggesting that when he surveys the rap scene he sees a minstrel show — a cacophony of buffoonish stereotypes.