Uh, I know you need that reptile
Kanye is likening his sexual organ to a reptile, and so describing its ferocious, animal nature, whilst also perhaps suggesting that it has a mind of its own. Some snakes can grow up to 30ft long so he’s extraordinarily (divinely?) blessed in this department, something which he has mentioned before.
From a religious perspective, this could also be referring to the story of Adam and Eve in the garden. Kanye is suggesting the woman is just as vulnerable to ALL forms of temptations, similar to Eve and the snake. This also insinuates that Kanye, too, is vulnerable, as both Adam and Even bit ate the forbidden fruit.
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