Sandy, now only waist high, looked up at Kat towering above her and mewed in terror. She looked so big to her now and Sandy felt so helpless. Out of reflex, she tried to cover herself with her hands as Kat leered at her nude form, but all she could do was wiggle the little round nubs that were her shoulders.
There was nothing she could do to resist and even if she tried, there was no telling what Kat would do to her. She could reduce her further, leaving her as just a head to be carried like an accessory, pulled out only to press against her crotch or she could take away her words entirely, leaving her only able to mewl like an animal. Or she could do something to Dan, now trapped forever as his insane sister's pussy.
She looked down, between Kat's legs to the hairless little slit that was her boyfriend, only his eyes left behind, gazing at her in horror.
"Go on, little kitty" Kat cooed to her, "Come give your Danny some love."
The words stirred something in her. She found herself wanting to do nothing more than put her face between Kat's legs and give Dan all the pleasure her tongue could manage. Just the thought of it was turning her on, not just because she'd be pleasuring her boyfriend, but because she'd be pleasing Kat. She went to touch herself without thinking and realised she couldn't. It dawned on her that she'd have to rely on Kat to help her get off and for some reason, this turned her on even more.
"Sandy, wait, you don't have to do this." Dan said, "Kat, turn her back!"
"Dan, wait." Sandy said, "I...I think I want this. I shouldn't, but....I've never been more horny than I am right now."
She stepped forwards and brought her face closer to Dan. She could see his lips tremble with conflicted arousal. Taking the plunge, she leaned forwards and slid her tongue into her lover. The feeling of rightness was almost overwhelming. Kat had clearly made it so that pleasing her had a huge positive effect on Sandy and had even changed how she tastes things, because now her pussy was the best thing she'd ever tasted.
"Nnnn...This isn't right." Dan objected, but it was half-hearted as he tried to fight through the pleasure
"Just shush and let her do her thing, Dan" Kat commanded as she put her hand on Sandy's head, pulling her closer, letting her tongue go deeper as she stood on her tip-toes to try to get a bit more height. "I altered her tongue to be longer and more dexterous just for you. Ahh! Oh, you're really good at this, Sandy!"
The praise filled Sandy with glee. Her Mistress was praising her! Wait, 'Mistress'? When had she started thinking of Kat that way. Either way, she redoubled her efforts, exploring Kat and Dan's folds with more vigor, teasing their clit and probing their depths. As she pleasured them more, she felt her own arousal growing higher and higher with no way to release it.
"Ahh! Wait! Sandy, I'm-" Dan's thoughts were cut off as he clenched around Sandy's tongue, juices flowing onto her face as he came. Her eyes went wide and she moaned as Kat's hips bucked while her hand on her head meant that each motion just pushed her face further into Kat and Dan's crotch.
"Oh god! Fuck yes!" Kat howled, riding the orgasm. For his part, Dan could only scream silently as his entire being was overwhelmed with pleasure.
Eventually, the orgasm faded and Kat collapsed backwards onto her bed, releasing Sandy as she bathed in the afterglow. Still more aroused than she thought she'd ever been in her life, Sandy mewled pitifully, rubbing her thighs together desperately.
"Oh, you poor thing. Come here, little kitty" Kat said
Sandy clumsily clambered onto the bed. At her height, it was quite tricky with no arms, especially as turned on as she was.
Kat lazily grabbed the tiny catgirl and pulled her closer, one hand snaking between her legs.
"Do you wanna cum too, little kitty?" Kat asked, to which Sandy simply mewed. "Okay then, but only if you beg and promise to be a good little familiar. "
Sandy gulped. She needed it. Really NEEDED it, but could she really just give in and accept what Kat had done, both to her and Dan?