Major Boobage

The obscene moans of Gina was the only thing that broke the silence, as both Tammy and Mike stared at her new body. Mike definitely had kept his promise. Gina now sported a body that looked like it had been sculptured by a skilled - and very perverted - artist. Not an ounce of fat anywhere where it didn't belong, and where her small tits used to be she now sported two massive globes about the size of her head, that didn't seem to care about gravity and were shaped as perfect as tits could be. Tammy realized that in her mental absence her hand had somehow found it's way to her brother's massive cock and she was just very slowly working it. But it felt good and in the right place, so she ignored that for the moment. The show her sister displayed was way too distracting. Not only for her, also Mike seemed very focused, albeit with a very pervy grin.

"You made them way more sensitive than they should be, right?" Tammy eventually concluded. The wide grin of her brother confirmed it.
"I... don't mind..." Gina moaned "It... feels... sooo goooood."
"And what else did you do to her?" Tammy wondered. A part of her was very jealous of how sexy Gina was now, but her inner pride kept her from asking for a similar treatment. Also she was really curious what else he had added. "Woah!" she suddenly had to let go of Mike's dick, as Gina went down and claimed it for herself and her new rack. Seeing how that monster of a dick was almost too small for her sister's new and very impressive tits was both mesmerizing and infuriating. A part of her, that she was trying to deny very hard, wanted that dick all for herself. But now the slurping sounds of her deep-throating the entire member was as disgusting as it was arousing. But then it suddenly clicked in her mind.

"You removed her gag-reflex?!" Tammy said with her mouth wide open. Sure giving a blow-job as a thank-you was a perfectly normal thing to do, especially with a dick that sexy, but she had not expected her sister to be able to take all of that at once. Mike grinned, and sweated, and moaned, obviously ready to blow his load.
"Not only..." he managed to answer in between. Tammy stared at her sister and tried to puzzle together what else might have had happened to her. But there were no other obvious signs, all she did was to kneel there, suck on that whole dick, and moan like a cheap whore. Then Mike came, and his volume was once again ridiculous. Gina was very eagerly gulping it down, but there was no way she could handle all that. Tammy stared down at her brother for giving himself those stupid changes, but he didn't seem to care at all. He was enjoying all this, obviously, that pervert! Still Tammy couldn't stop thinking about what else he had done to Gina, and eventually she got suspicious about how Gina was almost cuming herself.

"Wait a minute..." she suddenly had an idea. She gave them both a bit more time to finish what they were doing, but when Mike eventually pulled his dick out of her throat, she used that moment to plunge her finger right into her sister's warm, wet, and sperm-covered mouth. Immediately she begun to suck on that finger, and moaned like she was getting her brother's dick up her snatch.
"Did you... make her lips like... did you like turn them into an erogenous zone?!" Tammy asked with her mouth wide open, while Gina was going wild on her finger. Mike started laughing.
"You are smart, I give you that!" he confirmed her suspicion with a wide grin. "Figured it would only be fair that she can enjoy blow-jobs more if she can take any size now." Tammy wanted to say something witty in response, but actually she was impressed and a bit jealous. She looked back at her sister, who was very happily sucking on her finger and gave her a naughty look, and couldn't help but to think about how good that would be if she was sucking some dick for some reason. She did enjoy it in general, but it never got her off, and now Gina was literally getting off from just working her finger.

"So you are happy with your new boobs and skinny body?" Mike wondered. With a loud plop Gina let go of her sister's finger and grinned.
"This is like the best thing that anyone has ever done to me!" she exclaimed and got back up on her feet. She gave her new, massive jugs a good bounce, and her siblings an excellent show. Those gigantic knockers jiggling around was indeed mesmerizing, even Tammy couldn't resist and just had to give them a good squeeze. Which immediately sent Gina into moaning aloud.
"Damn.. even I suddenly want some that big." Tammy admitted.
"Oh you can have some, too, for a price..." Mike offered like the shadiest dealer. Tammy indeed had some requests, and those alterations Mike did did not sound bad at all. But what if he turns her into a super-slut, or give her a pig nose, or something? Realizing that she was still fondling Gina's tits, she **** herself off them, just to notice that she was back on Mike's now slimy dick a moment later.
"Horny?" Mike commented her relentless hand-job. Tammy rolled her eyes to play it off, but yes, she was indeed madly horny at the moment.