I have noticed a larger trend towards erotic dating, voyeurism, chat and other related activities. I believe most of these activities are dangerous and you should consider not only the moral factor, but also the addictive aspects and potential problems such activities could cause. This also goes for related activities such as swinging, clubbing, meeting strangers online to have sex with and so on.
I believe these activities are in a whole other category when compared to something as simple as erotic photos and video. As these activities involve other people interacting with you on an erotic level. First thing to consider is that they have a whole different spin when put in the light of scripture than erotic materials. As stated in this article and others, some erotic photo and video is permissible. So, when I say this, it does not mean you can watch whatever you like, as much of what is out there is evil in nature.
Hooking up with Strangers Online with Erotic/Sexual Motives - Whether it is chatting with some person, watching webcams with interactivity, voyeurism with interactivity, you doing webcams, etc. These activities are often sinful and some of them are risky/dangerous. With webcams and voyeurism, I believe such activities can be ok, however, you have to consider your self control and will it lead to something sinful? As the idea of hooking up with strangers online to have sex, this idea is very risky, unwise and often sinful (depending on the circumstances). It may seem like a thrill ride, until something goes very wrong. Just as there is that small percentage of technically permissible activities, it doesn't mean you should do it, as it could potentially lead to sinful activities. Use common sense here. If you are married, almost unanimously, you are cheating on your spouse if you are doing these activities. I am not saying 100% of all of this activity is a sin, but I am saying, it would be very wise to assume most is, particularly the hooking up one.
Clubbing, meeting up with strangers for sex, one night stands, etc. - If you are married, I don't even need to mention you are sinning in such circumstances, as generally speaking, you are doing it behind your spouses back.. Now, if somehow by an amazing coincidence your wife is OK with the idea of you having more than one woman in your life, theoretically, there are situations where it is not a sin (as it is not then adultery or violating your covenant with your wife). However, if you live in America, it would be unlikely your wife would go for that (better luck being struck by lightning).. Otherwise, doing it behind your spouses back, you are destroying your marriage and breaking your covenant with her, which is sinful.. NOW, if you are single, as you can see already, this is not a good habit to develop. For when you do get married, this type of habit can lead you to a reckless lifestyle that leads to other sin.
Swinging, Sharing your wife, etc - Now this one is adultery, if it involves your wife sleeping with other men. And swinging is basically swapping wives, partners for recreational sex. I have heard the arguments from these liberal or liberated Christian websites as they call themselves.. They claim that if you give "permission" to the other man to sleep with your wife, it somehow makes it OK.. Meaning, she is your "property" taking the Old Testament's verbage and claiming that since she is your property, it would be like lending your tools or car to a neighbor. I did a study on this topic recently. Now, techinically, it is not a sin for a man to sleep with another woman other than his wife (assuming she is not married and assuming his wife would not object).. So there are situations where this is permitted, as polygamy is not a sin. Many of the saints in the Old Testament had more than one wife often, concubines, etc. So, a man can sleep with more than just his wife (unless he promised himself solely to her in his wedding vows). But, swinging, is evil and the idea of a married women sleeping with some guy other than her husband is not permitted.
What about meeting a person for long term relationship through an erotic portal - Theoretically, this could occur, but it seems about as possible as finding water in a dessert. However, you have to ask yourself, "What are my true intentions?" And if you are married, why are you looking for another relationship? If you are married, you are to be faithful to your wife. If you are not married, I would suggest some other means in meeting a woman to be with. There are plenty of better ways to meet a Christian woman, such as church or normal online dating websites, college, the mall, etc.. However, I can see how meeting women online can be a better means, than offline, in some circumstances. Yet, meeting online can be done through dating sites, etc.
Massage Parlors, Strip Joints, Etc - Many of these type of places are not exactly the wisest to visit. With strip joints, I believe it is very unwise, as you could start coveting the women stripping. As Proverbs says regarding some women, For her house inclineth unto death, and her paths unto the dead. What is this refering to? It is refering to adulterous woman, women who forsake God, etc. It is refering to women who can ensnare your heart, ensnare your wallet, ensnare your time. It does not refer to all strippers, as some are not married and are not bad people. However, it has the addictive aspects of alcohol. And, alcohol, can steal your soul as that one famous song "Red Red Wine" says(says the same thing in Proverbs also). Remember, 9.5 times out of 10, these women do not care for you and are only concerned about money. Further, some of them are married and it is very unwise for you to be enraptured by a married woman and to lust after her, as then you commit adultery in your heart if you decide to go after her. And as you know, all men fall in temptation if not careful. Consider even strong followers of God, such as King David. You know he went to the roof of his palace more than once to watch Bathesheba. And what happened? He sinned in his heart, when he decided to have sex with another man's wife.. And what then happened? His child died, he lost his Kingdom for a time. All of this, because he lusted after another man's wife and committed the sin in his heart when he decided to go after her.. IN other words, going to strip joints, massage parlors, etc can be putting yourself in the fire and expecting to somehow come out not burnt. I would look at it like a bar. It can become something that consumes you, if you are not careful. You may succeed for a short time, but are you fooling yourself? Its kind of like the drunk trying to tell himself he has control over his drinking.