Gon' roll around with that B-Y,
Could suggest the letter ‘o’ is missing in between B-Y which makes this lyric “Gon' roll around with that BOY”.
Lupe is suggesting there will be a few scuffles & fights. Scuffles consist of people rolling around on the floor exchanging punches. These usually occurring in school playgrounds, along with the use of ‘BOY’, could suggest that Lupe sees this beef as child’s play.
This fits in with the next line as people tend to roll up their sleeves before a fight.
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