All the arguing seems unnecessary given the context of the thread. It is true that Futanari explicitly means both penis and vagina (It can be written 二成り for two + become or 二形 for two + form/shape/figure) but for the purposes of webms it is functionally the same in most cases.

If you want to see a futa fucking a woman, the futa's vagina isn't being used and you likely wouldn't see it unless the video has a very specific camera angle, so what difference does it make between being a futa or dickgirl? Same if they're fucking a man.

The only situation where it really matters is futa-on-futa, because it makes the difference between fucking a futa's pussy or a dickgirl's ass. But if we had another separate thread reserved only for futas fucking another futa's pussy the thread would always die because that type of video makes up such a small fraction of videos anyone ever posts, plus those videos are hard to come by like >>29643576 . I find true futas far more common in illustrations but in 99% of videos they are functionally identical to dickgirls.