Sexual Relationships 
Sexual Health 
A lot of guys I know complain why would they want a girl to dance on them and give them blue balls because they can't actually have sex or why they would ever pay for sex when girls today are much more promiscuous and open to it than ever before. Good question.
POWER
I think the main lure of sex that costs is that you are most assuredly in control (even if you're paying someone to whip you.) It is your fantasy it is what you want your only concern in making this as sexy as you need it to be. You move her where you want her how you want her she does what you say and for the regular guy this is incredibly appealing. It is something you just can't have with a normal girl and yet it is something a lot of guys enjoy even if they don't admit it.
GREAT EQUALIZER
Any guy can have a very hot woman for night. This is a fact. Engaging in the occasional prostitute makes you realize hot one nighters aren't just fantasies only to be enjoyed by the mega famous and successfull. Sex with a woman is right at your fingertips for anyone with the cash. Ironically, it can make you feel like a woman's beauty is less important since beauty can be bought but a personality is priceless.
BEAUTIFUL DARK FANTASY
Guys just have a very unrealistic expectation for their sex lives and with the advent of free porn this is even more true. The logistics of the fantasy are incredibly difficult--a perfect 10, who is open to having sex pretty quickly, who doesn't have any stds, who won't make you use a condom, who won't get pregnant...so much of this screams unrealistic. Yet, such a experience is commonplace for a prostitute to make real.
BUILT TO LAST
Many prostitutes have a fake ass and fake tits. This can be very difficult to get past for many guys and yet no woman you date will ever be built like your porn addiction has led you to expeect and crave--they won't even come close. High class prostitutes are downright gorgeous and average prostitutes are typically pretty girls who got in a bad way. You just won't get that from a regular woman and perhaps you shouldn't want it since craving a body over a person is pretty much the defnition of dehumanzing someone.
I'll finish by saying I don't engage with prostitutes because I feel like the business is riddled in such abuse (of pimps not paying their girls etc.) and I can't help but think about their own personal stories yet I don't look down on guys who do this as simply unable to get laid. I can see why a lot of guys who can get laid plenty with many girls would still fall for the lure of paid sex. As for strippers, I think most people even women don't have that much of an issue but the logic applies the exact same.
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