Usually it is the erection that follows the vision. So following hand in hand with erection?

I think I understand what you're saying but I think the word you are looking for is "lust", a passionate desire for something. Sexual desire and its physical manifestation - sexual arousal (erection in men) has led many people away from truth and righteousness and indeed corrupted them to do very evil things. David is a great example, he sent his servant Uriah to the front lines to get killed just so he could take his wife.

In our day pornography is polluting the minds of people. People are not respecting each other as persons but looking them as objects to satisfy their lust, tools for pleasure. Sex is sought out as a daily ritual and homosexuals and transgenders are parading through the streets, proud to be the champions of perverted lusts of the flesh. Perverted men and women are even looking to legalize pedophilia and ruin the lives of countless children. And sex robots are being sold because why not have your own mechanical sex-slave stashed in a closet?

Marriage is the best and only way a man should enjoy sex, with his wife. Having sex outside of marriage in any context will always lead to bad consequences.