I was under the impression that as long as you're not spilling seed wantonly on the ground and as long as you're not fucking someone other than your spouse there isn't really anything in the bible to prevent enjoying porn.
There is little or no biblical support for *most* of the sex-related prohibitions variously endorsed by churches throughout history. In some cases, church teaching even blatantly contradicts scripture.
Take the concept of "sodomy", for example. It means mouth and/or butt sex, right? NOPE. Ezekiel 16:49 explicitly states that the sin of Sodom and Gomorrah was that they were arrogant, heartless, and overfed, and didn't help the poor. So, as one of my friends recently quipped, the actual biblical definition of sodomy is "voting Republican"... lulz xD
Another good one: many churches have historically condemned masturbation as "onanism", another clear and obvious misrepresentation of scripture. Onan was killed by God for "spilling his seed", but his specific act was not masturbation but rather coitus interruptus
. And even that act is not specifically prohibited in the Bible; rather, it was his disobedience to a direct command that he father children with his dead brother's wife that got him off- err, offed. His sin was going through the motions of obedience and trying to make it look like he followed through, while secretly disobeying. (Side note: can you blame him? If my bro died and you made
me bang his widow, I'd do my best to enjoy it, but the last thing I'd wanna do is knock her up)
Those two are among my favorites because the popular mainstream doctrine directly contradicts the bible... most of the other cases involve proscriptions that have no clear basis in scripture but rather stem from tenuous interpretations of really generic language (like "be fruitful and multiply" meaning birth control is a sin, no matter how overpopulated the Earth gets or how many people suffer from starvation).
Stuff like this is why I've concluded culture and politics are the primary drivers of church doctrine, and the religious/theological rationale is generally an afterthought.
EDIT: Also lust is one of the seven deadly sins.
The seven deadlies aren't in the bible either. They were a product of medieval pop culture, back when the good book was only printed in Latin and nobody could read it. They were really intended as a sort of quick-reference test for laymen evaluating possible sin... if a specific action resembled one of those things, it was probably a bad idea and you shouldn't do it.