Through several hoops

The easiest way to fulfill your fantasy of fucking your sister and impregnating her is obviously to just make **** legal while eliminating any possibility of genetic or birth defects, but herein lies the problem. You don't want to normalize ****.

Part of what makes the possible incestuous relationship between you and Vivian so exciting is exactly because of the sheer taboo of it. You want your sister to willingly get fucked and impregnated by you while still wholy cognizant of how wrong the relationship is in the eyes of society. Hence you can't just normalize ****, nor make the erasure of possible genetic defects in offspring of sibling **** an "Old Rule". Making it an "Old Rule" might still result in the normalization of **** due to the elimination of the biological reason of why **** is problematic.

You mull over the thoughts as you leave the coffee shop and get on a bus. As you sit there, the other passengers ignorant of your lewd thoughts, you finally decide on 2 "New Rules" as the basic.

"New Rule: The existence of the owner, Arthur Drake, and his sister, Vivian Drake, as well as their resulting progeny, will not be affected by any retroactive changes brought about from the usage of the rulebook."

"New Rule: As of the writing of this rule, any offspring resulting from sibling **** shall no longer in any danger of genetic and birth defects."

As you finish writing the 2 rules, you take a moment to see if there is any sudden changes to the world around you. The first rule's purpose is obvious, you don't want yourself or your sister to be "erased" by a sudden change to the world due to an "Old Rule". The second rule meanwhile is just a roundabout way for you to make **** "safe" but still a taboo, at least for the moment. Seeing there is no apparent immediate changes to the world, you decide that making the rules "New Rules" was the correct decision.

Exiting the bus at your bus stop, you walk a bit to your home. As you walk, you think about how to best win over your sister. The two of you are close, you know that, but the thought of just confessing your feelings to her directly fills you with slight trepidation. If you fail, you might ruin your relationship with Vivian forever, and you can't afford that. Though if you succeed, it will only be a matter of time until the cat is out of the bag and you and your sister become social pariah. You can handle it, but you would prefer if your sister doesn't suffer just because of your selfish whim.

What to do? What to do?

You contemplate different ideas as you enter your home and go to your room. Fortunately, your sister has already gone to school so you have all the time to think. Of course, you can just go ahead, seduce your sister, and then hope for the best while using the rulebook to solve any problems that might arise in the future. But hindsight is never 20/20 and you aren't that bold to just gamble on your luck like that. Talking about the future, there is also the question of how you shall take care of any children you and your sister will have. Obviously you want more than one child, in fact you intend to keep impregnating your sister again and again as much as you can, but children will without doubt put even more strain on your financial situation.

Taking a time away from your thoughts, you browse your collection of books and novels for inspiration. Sure, you said that you are mostly busy with college and work, but that doesn't mean you don't have a hobby. Just like any other boys out there, you play video games, as well as reading some fictions here and then. Your favorite setting is fantasy, in particular high fantasy. You sometimes imagine how it feels to live in a fantasy world where you are free to do whatever you want including fucking your sister, where no one can't oppose your strength. And as a bonus, no bills.

The more you think about it, the more appealing the idea becomes.