Some multiple things.

Amy hummed before nodding to herself, "Make me have an twin sister." before a reaction can fully appear on John's face, Amy holds up a hand to silence him and continues, "It'll test your limits and is quite easy to notice, plus I'll get a best friend."
"How do you even know you two would even get along." was his question about this hypothetical twin that Amy would get, he was pretty sure that his truth touch doesn't work and this won't do anything either.
"If you are so worried about it, then make it so with your special hands." Amy chuckled, "Which are magical still, but you know what I mean."

Figuring that nothing could really come out of it, he continued to massage Amy's pussy as he thought out how he wanted to word out the claim that Amy had a twin sister. It took a moment before he took a deep breath and spoke out loud... words in a deadpan voice, ready to be frustrated and disappointed. "You've got twin that pretty much the same in appearance as you, you two are the best of friends and I am the only one who can actually tell you apart."

"Again, stating what is already here. How could I be so foolish ask for another sister" declared Amy as she looked at her twin who lay beside her, "Do you forgive me, Samie?"
Samie just looked at the ceiling as John continued to massage her and her sisters' pussies before asking a questioned that had been stewing in her mind ever since their Bother had come in and talked about how touching them he could make anything the truth, "So how do you know what is the truth after you said it?"

The unintelligent "Huh?" that came from her siblings just made Samie groan, "What you said becomes true, so you'd never know it was false, correct. Because it has been always true."
"Again, Huh?" was all she could get from Amy.
"Say for example that you gave me extra eyes, then I'd always have those extra eyes, you'd just never remembered me not having them." Samie tried to explain, but it confused them, that she did see clearly on their faces.

"Samie has 4 set of eyes much like a spider." states John before sighing and looking at the small eyes that his sister Samie would only open in privacy of him and Amy, "See, I would know if you ever had more or less then eight eyes."
"I wonder how many eyes I had before this point in time..." questioned Samie knowing she had a different amount of eyes, but not from how much, she then smiled and brought herself up to John's face a whispered in something she wanted him to repeat into his ear. "Can you repeat that?"
"Sure... don't see why you'd want me to, but sure I'll indulge you with my mouth and fingers this time."