Agree that it probably belongs in Amateur Porn or Bondage/SM
I respectfully disagree though-I don't think it's about being pegged, those of us that have had 3-somes with a girlfriend that loved strapping in and hammering another girl find these pix appealing.
There is no greater nut you will ever bust than looking across the bare back of a hot girl as you spit-rod her with your woman.
BTW, I've never been a catcher, Alpha all the way