Flow so nice you ain't gotta put a rug on her
The word “flow” is being bent here to also sound like “floor”. Rugs are decorative items used to make your floor look better, but Wayne’s “flow/floor” already looks great
Also another underlying Wayne-esque menstruation reference which follows on from the previous line, specifically the “blood donor” bit; her flow (period) is so nice there’s no need to rug up that pussy, just donate it to Wayne and, uh.. let it flo'
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