I think they meant "grow a big rubbery one," which is referring to the tumescence of the corpus spongiosum of a penis. Though I believe the comment to be faceti

I think they meant "grow a big rubbery one," which is referring to the tumescence of the corpus spongiosum of a penis. Though I believe the comment to be facetious, and no sexual arousal was actually, or has actually been, achieved due to content of their original claim.