For now

Adam stood in front of his older sister and gazed at her large breasts as he considered his next move.

I really want to experiment on Mom and Jackie, but at the same time I want to see how far I can push Kathy. I guess I’ll stay with Kathy for now.

“Your tits are really nice, Kathy. I love looking at them.”

Katherine smiled again. “Thanks Adam, you’re so sweet!”

Adam nearly laughed at the absurdity of Katherine calling him "sweet" for saying something that would have gotten him slapped mere minutes ago. Suddenly, an idea came to him that sent shivers of excitement down his spine and made his manhood twitch.

“Can you jump up and down for me, Kathy? I want to see your boobs bounce.”

“I don’t know if I want to do that,” Katherine frowned deeply, as if she were trying to remember something important. “It sounds a little… um... wrong.”

“If you don’t do it, I’ll stop looking at your tits.” Adam smirked and made a show of turning away from her.

Katherine’s eyes widened comically. “N-no, don’t stop, Adam! Here, look!”

Adam turned to face Katherine and was rewarded with the sight of his busty older sister’s breasts bouncing and jiggling as she hopped up and down.

Hm. So implanted preferences and desires can be used as effective tools of manipulation without any direct use of the logic device. That is really exciting news! I wonder what the limits are?

“Okay, that’s enough for now," Adam said.

Katherine stopped jumping and sighed.

“Please, Adam,” Katherine cupped her breasts again and stepped closer to her brother. “Just look at my tits. I like it when you do that.”

“Can I touch them?” Adam said.

“What?!” Katherine stepped away from Adam. “No, you little pervert!”

“If you don’t let me touch your breasts, I won’t ever look at them again.”

“No!” Katherine looked pained for a moment before she crossed her arms and shook her head.

“You’re an asshole, Adam,” Katherine glared daggers at him. “An evil person. I can’t believe you’d stop looking at my tits to try and bully me into letting you grope me. I’m your older sister, for fuck’s sake! You have to look at my tits!”

Adam frowned.

Why did Kathy let me manipulate her into bouncing her breasts for me, but draw the line at me touching her? There are still so many things I’ve yet to understand about the logic device’s capabilities. Well, time to salvage this!

“That’s the floor, right?” Adam said as he pointed down to the white carpet beneath them.

“Obviously!” Katherine glared at him.

“And you stand on the floor.”

“No shit, Sherlock!” Katherine grounded out.

“You always forgive me completely for anything I apologize for.”

Once again, Adam was graced with the sight of his sister adopting that blank mindless expression he had come to enjoy so much.

After about a minute, Katherine shook her head and glared daggers at her brother.

“I’m sorry for what I said earlier, Kathy.”

Katherine's facial expression brightened instantly. “It’s cool, little bro! Water under the bridge.”

Then she hugged him.

Adam’s brain short-circuited as he felt Katherine’s huge naked mammaries mashed up against his chest.

Soft…

Adam’s hands moved before he could stop them and before he knew it he was kneading Katherine’s generous ass through her jeans as she hugged him.

“Ew, you perv-”

“S-sorry!” Adam said. He removed his hands from Katherine’s ass.

“It’s okay, Adam!” Katherine looked up at him and smiled.

Adam chuckled darkly.

Oh, I am so going to **** this!

He reached a hand between Katherine’s legs and rubbed the area around her pussy through her pants.

“Sorry!” Adam said before Katherine could react.

“Mmm… I forgive you,” Katherine gazed at Adam adoringly with her azure eyes and deepened her topless hug.

Holy fuck, this is so twisted.

An idea began to take root in Adam’s mind.

“Kathy,” Adam said.

Katherine broke their hug and looked up at Adam with questioning eyes.

“I apologize for what I’m about to do.”

“Shhh… It’s alright, Adam,” Katherine smiled warmly and placed a hand on Adam’s shoulder reassuringly. “Whatever you’re going to do, it’s okay.”

Adam reached out and seized his older sister’s breasts in both hands. He kneaded and massaged them. He tweaked her nipples and his cock twitched again. He poked his sister’s boobs and watched with disbelieving eyes as her titflesh jiggled enticingly.

Adam withdrew his hands from Katherine’s breasts.

He took another step towards Katherine, reached behind her, and caressed her firm ass through her jeans. He slipped one hand under the waistline of her pants and squeezed her bare right buttcheek.

Through it all, Katherine looked up at him with accepting, unjudging eyes, eagerly forgiving him as he violated her in ways that would have repulsed her deeply under normal circumstances.

She’s not even saying anything. Is there a time limit at all? Would she let me do this all day because of one preemptive apology?

“Adam!" a female voice called out from downstairs. "Come out in the yard and help me!"

“That’s Mom,” Katherine’s tone was authoritative in the way only that an older sister’s could be. “You’d better go see what she wants.”

Adam paused for a moment.

With the logic device, I really don’t have to help Mom if I don’t want to. I can stay up here with Katherine if I wish, and I really do. Then again, I’ve really been looking forward to experimenting on Mom. Or maybe I’ll pay Jackie a visit, instead?