>>280056298
futanari is abusing the male lizard brain's reaction to seeing another penis in proximity to a female
>bitch is getting fucked
>I should be fucking that bitch
that's why it's so prevalent in VRChat even among "straight" normies

cuckoldry is similar but instead of acting on the urge to fuck their conscious mind decides they can't do it but they jerk off anyway and form a pavlovian response when they climax and someone else is railing the female