What?

He tests it by making his Meg into Hot Meg

"This is probably just a waste of time, but I might as well see if it works." Brian says, having read the how the book works in the front. He'd gotten the book when it literally fell out of nowhere when he was walking outside.

"But how to test it. How...to...test...it..." He drawls out boredly, drumming his fingers on the kitchen table. All of a sudden, Meg walks into the room, heading for the fridge.

"Hey Brian. Writing a new book?" She comments casually, not really paying attention. She opened the fridge, bending over to see what's inside. This gives Brian the unpleasant view of her unshapely backside.

"You could say that I guess." He responds, silently disgusted by the view he has. 'Damn, if only this Meg looked like that one from the other universe. Now that would be...a...view.' his thoughts trail off as he looks back down at the book. 'Now there is an idea.'

He opens the book quickly and writes down the rule he chooses.

New rule: The Meg Griffin of this Universe will always look like Hot Meg from the other Universe. Nobody but the rulebook holder will notice the change.

'There, if that doesn't work, then this...book...'

His thoughts come to a halt as he looks back up to see a heart shaped ass in a skirt bent over in the fridge. The sight has him aroused as he realizes that it's still Meg and the book works.

'Sweet mother of God, I can do anything with this! I can stop wars, end hunger, cure cancer! I can...' His eyes catch Meg's ass again and his thoughts derailed.

'Then again, maybe I should...test this some more. After all, don't want to drastically effect the world with something that hasn't been completely and thoroughly tested.'

When it looks like Meg has found what she's looking for and is standing back up, Brian has to determine what he'll do next.