I would be willing to bet that most scat porn probably isn't real. What they most likely do is go about it just like any other anal scene, and find a couple people who agree not to eat for a day or two.

They probably then get enemas and/or colon cleansings, and then -- just before the scene is filmed -- probably take some of those little 'fun size' Snickers or Baby Ruth bars, smears them with KY or carrageenan, and then stuff as many of them up their butt as they can fit. Then they probably wait for the inside of their butts to melt them, and 'poop' them out onto each other.

Think about it. Would it be easier to find at least semi-attractive people who were willing to do what I just described, or people who were actually willing to shit on each other and then have sex while all covered with actual human shit? I'd say that plenty of those scat porn pics look more like the people are covered with chocolate and/or caramel than actual feces.

There are lots of videos where people eat food out of other's butts, or slurp semen (assuming it's even real semen) out of each other's butts, so it's basically the exact same thing as that. Some porn director probably just asks one of those same people, "Hey, would you eat a Baby Ruth bar out of someone's butt too?"