Setting the stage for endless anal sex.

The discovery of being able to add a new rule on a whim changed everything.

His initial change of women preferring anal sex over vaginal was made under the assumption that he could only make changes that affected pre-existing rules. Because of that, in order to create the world of his dreams, he'd have to change each individual rule one by one, carefully constructing his world piece by piece. A daunting task, to be sure. Especially considering the rules weren't seemingly placed in any obvious order.

But the idea of interjecting a new rule into the collection. He paused at the possibilities. How would his new rule affect pre-existing ones?

One way to find out.

• The only non-reproductive sex that humans have is anal sex.

Swallowing once, he clicked submit.

Immediately a small pop-up message appeared on his phone, displaying the following words: "This change affects other changes listed in the app. Would you like to automatically modify existing rules as to not create any lasting conflict?"

He paused, reading the message once more. This solved his earlier question. He was actually amazed at the thoroughness of this app. Whoever made it really was brilliant.

Adding the little check to ensure that the message wouldn't appear again, he clicked yes and waited. The app buffered for a few seconds and reloaded in an instant.

Glancing at the immediate rules displayed on the screen, he quickly confirmed that no lasting conflicts remaining. He grinned as he read.

• Sex is the act of a man putting his penis inside a woman's anus, while breeding is the act of putting it in her vagina.
• Couples very rarely engage in the act of breeding, the only ones doing so being two individuals who wish to have children together.
• All sex acts involve a person's ass.

He stared, dumbfounded at what had happened. If the power of this app was to be believed, the only sex people would now be interested in would be anal. He scanned his room once more, again looking for anything out of place, but found nothing. Still, he believed in the power of the app before him. He turned back to his phone, and started typing new rules.

• Oral sex is the act of using one's mouth to either lick or rim another's asshole.
• Oral sex is pleasurable for both parties, and is often used as an act of foreplay.
• Everyone enjoys having sex.
• It is extremely common for man to let their partners fuck them anally and for women to enjoy doing it.

That last one appealed to his kinkier side. Being highly interested in anal, he'd always been curious to try pegging. But he knew Sara and most girls out there would avoid the subject entirely. Now, he's successfully changed that.

He continued:

• Guys only get hard when giving or receiving oral sex.

Rereading that rule, he paused. In his excitement, he'd forgotten to consider one that fact that if guys only got hard with anal, we wouldn't be able to reproduce. He changed that before continuing.

• Guys only get hard when their dicks come into contact with a pussy, or when giving/receiving oral sex.
• Girls only get wet when their pussies come into contact with a dick.
• Condoms and any form of birth control don't exist.

He grinned. With his new rules, that last one was no longer required.

Putting his phone down, he scanned his room once more, feeling disappointed that nothing had immediately changed again. As he finished his search, his eyes locked on the dresser next to the bed he and Sara shared. There was one way he could find out if he'd been successful.

Opening the drawer, he took a step back in surprised, shocked at its contents.

Like he suspected, the box of condoms was gone. Instead, in its place was a large black strap-on - obviously used, from the look of the straps. He stared at the thing, stunned, roughly judging that its size matched his own cock when fully aroused. Blinking, that's when he noticed the scattered bottles of lubrication tossed around the sex toy. Bottles of various size, brands, and colors read various flavors or lasting time. Naturally, you'd need lube to have proper anal sex. And clearly he and Sara were well stocked.

Stunned with awe, he slowly went back to his phone - the app still open on its screen. It worked! The app had worked! With this much done, there were only a few changes left he wished to do before perfecting his world.

• Everyone is fine with both men and women walking around topless.
• Girls aren't required to hide their boobs or wear bras.
• It's common to walk around in one's underwear when indoors.

The sound of a door unlocking brought him back to reality. Quickly locking the phone and tossing the device, he entered the adjacent room just in time to catch a glimpse of this new arrival as they walked into the apartment.