I agree the first point, but not the second. If it has a urethra, that's a penis, not a big clit. But if the big clit is used for penetrative purposes, it's still a big clit, not futa.

I'm in a similar camp to @xelacus. If a urethra runs through it, I'd say it's a penis

Where should the line be drawn between big clit and a futanari whose clit grew to become a penis? I think there's two distinctions. 1: if the clit has a urethra and ejaculates, it's futa and not big clit. 2: if the PRIMARY sexual function depicted in the doujin is using the big clit to penetrate someone else, it's futa. Just my opinion. Anyone else have other thoughts?