One hangup in this regard, is when Jesus said not to lust after a woman with your eyes. How do you do this visualization stuff without running afoul of “committing adultery in your mind”? The answer to this will also address the whole porn issue too. Two birds with one stone.
Here’s the verse. I encourage you to read all of Matthew 5 in context (in KJV, not the PC NIV).
“Ye have heard that it was said by them of old time, Thou shalt not commit adultery:
But I say unto you, That whosoever looketh on a woman to lust after her hath committed adultery with her already in his heart.”
Adultery is a sin with a married woman. The context makes clear this is talking about married women. I don’t recommend EVER lusting after another man’s wife. End of story.
As for lusting after unmarried women, my overall impression is that Biblically this was less of a big deal. After all, it’s an impetus to marriage.
When you’re looking at a woman, there’s appreciation, there’s lust, and there’s lust with intent, looking for opportunity to fornicate. In my opinion, the last one is the sin to avoid. If you would never fornicate even with full opportunity because it’s against God’s law, then no matter how you look at a woman I don’t think you’ve sinned that grievously.
It’s also worth noting that the passage is hyperbolic and delivered with a specific rhetorical intent. These are not all absolute commands for all circumstances and times. They are an attitude reset.
As for porn, it would be better to slake your burning lust with wife(s), but given the practical alternatives I view it as mostly harmless when kept in its place.
We are not angels, so manage the greatest degree of righteousness that is practical and effective, making the necessary allowances for your sin nature to achieve maximum Kingdom performance. God is not fucking around with an abacus counting your dirty thoughts, he is evaluating your soul harvesting capacities to determine your future rank in his world-conquering army.
In my opinion, results are what counts and personal holiness for its own sake is masturbation… pun intended.