Here’s my hypothesis as to why futa is as popular as it is assuming that the vast majority of futa lovers are guys. Men have dicks, and men know how good it feels to stimulate it and shoot cum out of it. On the flipside, men will never exactly know how girls feel when they cum from their pussy getting stimulated. So, when a guy sees a futa cumming or getting >her dick stimulated, he knows EXACTLY how that futa must be feeling. Seeing a girl cum and experience the EXACT feeling that you know all too well is probably what makes futafags enjoy futa. Plus, knowing that the futa is capable of experiencing the exact same pleasure the viewer can probably help with self-inserting. This theory all falls apart for faggots who enjoy getting fucked by futas but whatever.