You ain't accustomed to going through customs
You ain't been nowhere, hah?
By saying that that “you ain’t accustomed to going through customs” Kanye is implying that he is. In other words, he is a jet-setter. His lifestyle makes him able to fly to exotic places, but “you ain’t been nowhere.”
Also note the word play with “custom” and “customer” in the previous line with “accustomed” and “customs”, as well as “curses” and “cursive” in the lines above those.
ps : note the trademark Kanye HAH?!
He also emphasizes that one is not universally cultured unless they have experienced the practices and customs of other cultures.
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