Strictly speaking, it's a win-win. It is proven that most successful people come from loving households. Obviously, im not saying that you need to be spoiled or rich to get far in life, but at least your family should teach you how boundless love feels like. The same can be applied to sex. If a guy has casual sex with his sister, both will benefit from it on a psychological level. If she is younger, onii-chan will teach her what to expect and how to maximize the pleasure. If she is older, sister will make her lil bro more confident and raise his testosterone levels tremendously by showing him the ropes. AND it improves society as a whole, because betraying your sister OR lover is possible, but sister AND lover? Pretty much will never happen. Hell, i'll even throw in a wrench: any guy will be willing to fight a bear barehanded, if it meant that his sister-wife and mother of his children will survive.
Think about it logically. What can be sweeter and warmer than a loving embrace of someone, who shared her childhood with you? We all say that "there is someone for all of us", but i can bet any sum of money that no person on this planet has as much potential to be a loving partner as your sister. Of course, it is scary, like all morally right things, i bet first people to fight for blacks were scared too, but it will fade away, once you fully embrace your sister's bare body and have sex. Sex between siblings is good on logical, moral and primal levels, think about it for a while.
Phase Connect.
