What do you do, now?

Make some minor changes first

After considering it for a moment, you decide to add some perks to yourself and anyone you'll bring in on this now. Also, you should probably cement your authority, first...

Old Rule: Rules marked as "Old Final Rules" cannot be contested by co-owners, under any circumstances, unless the owner has decided to question it themselves.

Old Final Rule: The above rule is an Old Final Rule.

Old Final Rule: Only the owner of this book may write Old Final Rules.

You quickly re-write the rules about ownership and co-ownership as Old Final Rules, to keep them in place.

Old Final Rule: The owner and co-owners of this book will be immortal, until they decide to revoke their immortality.

Old Final Rule: The owner and co-owners of this book can alter their bodies at will, but the baseline of their bodies will be a personal perfection, as specified by the mentally and physically healthiest view of themselves that they have. This will not lead to an inflated ego, and if they have a poor opinion of themselves, they will retain their current body, albeit with changes to help their mental state improve. Additionally, any conditions they see as a deficit will be cured.

You immediately notice a change in your body. You feel some of your belly fat disappear, your arms broaden a bit, and your various aches and pains simply dissolve. You sit up a bit straighter as you feel your scoliosis resolve, and you have to remove the orthotics from your shoes as your flat feet develop an arch.

Finally, you feel your penis stir. You can immediately tell that it's become thicker, and longer. You're dying to see how big it is...