Blair began to pant heavily, her shaggy body musky with primal desire. Unable (or unwilling) to contain it for one second longer, she leaped on top of Sierra. Sierra decided to just go with it; it wasn't like she and Blair hadn't experimentally French-kissed before, after all.
Blair wrapped her muscular arms around Sierra's shoulders in a strong embrace. She vigorously licked Sierra's nipples for a bit. She quickly moved on, bored by the lack of hair on those parts. She slipped down to Sierra's pussy and dived into the jungle of coarse, dense red hair. She purred at the feel of Sierra's ticklish hairs brushing over her face as she licked and bit at her older sister's pussy. Sierra herself was groaning in delight as Blair hungrily ate her furburger. Who knew Blair (who had never taking sex beyond Frenching and groping before) was so good with her tongue and teeth? Sierra bit her lip with pleasure as the tips of Blair's tusk buds tickled the place where Sierra's thighs met her crotch. Blair gently ran her sharpened nails down the insides of Sierra's legs as she tongued and nibbled, not hard enough to break the skin but definitely enough to tingle erotically. As Blair bit down of her sister's throbbing clit, Sierra felt the tremors of her orgasm begin. Her toes curled as the waves of electric pleasure surged throughout her hairy, muscular body. She threw back her gloriously shaggy head and howled like the animal she looked like.
Blair gleefully joined in the howl as she pulled her head out of Sierra's bush, rolling onto her back. As she lay there, Blair felt her tiny tusks and horn buds with her fingers. She gave her semi-clawed hands a loving look before rubbing them through her pelt of red vivid hair. "You know, Sierra..." Blair said, smiling, "...this body isn't so bad. I... I like it. Love it, more like." She felt her tiny horn buds again. "Hey, are these dinky little things ever gonna grow bigger?"
"I doubt it," said Sierra. "It only goes further if you take more Beast Juice. This is actually a bit extreme for one dose. Guess I should've gone with two drops. It was an old bottle; it probably went off or something."
"Any left?" asked Blair.
"Yeah," said Sierra. "Why?"
Blair's eyes lit up. "Because I wanna go further, dumbass! I want a pelt of fur, magnificent horns, mighty tusks, wicked claws, all of it. Help me change more, Sierra! I NEED more!"
Sierra shook her head. "You'll go feral, Blair. This stuff fucks with your brain. This constant horniness will just get worse, for one thing. You'll get more primitive in general, too. The witch said so."
"Maybe that's what I want!" Blair snorted. "Maybe that sounds cool to me! You gonna help me or not, Sierra? You always have in the past!"
Sierra sighed. "Alright. Unlike our dear mother, I think you're old enough to make your own decisions. I'm good as I am, but you can goo full beast if you want." She ran back to her room and came back with the bottle of Beast Juice. "We should get out of here. I don't feel safe with my monster mom devolving in the next room and getting horny as hell. We'll go to my friend Meadow's place. You can drink it there."
Blair nodded. "Got it, Sis."