Let's move on to something a bit more... physical.

You hummed for a minute, a bit lost as what to do now. It was clear that you could completely mentally control someone using this book and they wouldn't put up a fight against it no matter what. If it would have changed her behavior as well, Katrina wouldn't have been here to begin with. For that matter, you checked when you made the Old Rule into a New Rule, there were no additions or subtractions between Rule changes. So, you assumed, it was reasonable to say that unless you did something like make it to where only women were allowed in the coffee shop as an Old Rule, people would not change their behaviors immediately even if it was something that they disagreed with. Long term testing was still required but for your purposes, this works out just fine.

So, now that your mental dominance was most likely assured, what could you do physically? After all, the Rule Book said that it changed the rules of the place. But, what constitutes a rule/law? Could you change gravity? Perhaps change people physically? You were sure that if you used an old rule, you could get every girl in this room to be wearing cosplay. However, could you change them, that is the question.

Well, Katrina looked to be about a C-cup, right? Hmmm...

"Old Rule: Women inside this building are D-cups or higher."

You expected one of two results, either Katrina and the rest of the Under-D crowd would disappear or....

You watch in amazement as her chest expands outward, though it is harder to notice since she is wearing a sweater but you can tell that her chest definitely got bigger somehow.

"Ms. Kyles, we've heard about some anomalous effect in this shop that causes a girl's boobs to get bigger. Now obviously as a guy, I can't tell if there is a difference. Have you noticed anything like that?"

It seems that for a second she wants to lie, but her eyes go back to your clipboard and she nods.

"Yeah. It's part of the reason why I come here to write some of my... racier fanfic. Now, I am not lacking in assets, but feeling them swell up to a D has to be my favorite part of coming here." You can tell, even with your inexperienced eyes, that she is preening under the attention.

She giggles, causing her chest to make just delightful movements.

"One of the best things ever is to bring A-cups here without them knowing about this place and watching them freak out before we tell them." She adds.

Interesting. It seems that your increasingly cool Rulebook either implants false memories to rationalize the change or more insanely alters the very fabric of reality to make what you state in your book true.

Still, this is a change that can be accomplished with some plastic surgery. Let's start getting creative.

"Old Rule: Whenever a female enters this store, their ears become furry cat ears that match their hair color and are relocated to the top of their head. These ears are highly erogenous zones, about 3/5's as powerful as her clitoris when both are rubbed. Only those with clipboards may rub them in public, as when they do so it is not seen as a violation of privacy."

You watch in amazement as her ears slowly turn into cat ears, and climb up to the top of her head.

"Mrs. Kyles-"

"OUCH! Can you be a bit quieter, my ears get really sensitive in here. I know you guys are talking at the same volume, but it seems extra loud..."

Whoops. You should have thought that through. Though, her cat ears are about the same size as they would be on a real cat. You decide to alter the Rule a bit.

"Old Rule: Whenever a female enters this store, their ears become furry cat ears that match their hair color and are relocated to the top of their head. These ears are highly erogenous zones, about 3/5's as powerful as her clitoris when both are rubbed. Only those with clipboards may rub them in public, as when they do so it is not seen as a violation of privacy. These ears are proportional to the size of the female's head, and naturally adjust so they both keep the hearing increase while not making noises that are easier to hear sound any louder."

You almost stopped, but you noticed the dog with cat ears in the cafe.

Let's just change female to woman instead annnnnd, boom. No more Dog-Cat.

"Sorry Ms. Kyles, I didn't mean to yell."

"Yell? When did you do that?"

Hmmm, if a memory directly contradicts the latest rule's canon then it is retconned? Neat.

"I was wondering, how does it feel to sprout cat ears whenever you enter this place?" You lean over the table and begin to idly rub them. Katrina flushes.

"O-o-oh, y-y-you know.... U-us girls are...," her breathing quickens, proof that not even nerves are immune to your control, "resilient... w-w-we find, oh god, we find ways to adjust." You remove your hand, watching her pout with the sight bringing you supreme joy. No, you weren't going to be the one to make her come today. Her fingers or one of her 'electronic boyfriends' would take care of that for you.

Hmmm, now this leads to an interesting dilemma. How far could you take this? Could you give yourself superpowers? Well, beyond having the Rulebook, anyway? You really didn't want to try that out just yet, just in case it somehow leads to you losing the Rulebook.

You suppose that there are two ways to go about testing from then on. Either you continue to alter the rules and ask Katrina questions until she inevitably caves and masturbates in the bathroom, perhaps using her new-found love of ear-play to make the process go faster. Or maybe you should see if you can do anything to the Rulebook proper. You're not sure how to word it in such a way as the book becoming an organization, but perhaps you could think your way around it?