Selena decided to go for it. After all, what could be better than activating her slumbering wolf nature AND fucking the hottest tail in the pack? "I'm gonna be real with you, Luna. I want you to be more than a sister to me."
Luna's lupine ears pricked up. "You... what? You mean... like... lovers?!"
"Yeah," said Selena. "I need to feel your furry arms around me, your tongue between my legs. I need you to claim me, Lulu."
Luna's tail was darting to and fro in shock. "Where in the name of the Moon did THIS come from?!"
Selena placed a hand on Luna's luscious hip, pleased that her oldest sister didn't recoil. "Don't be so innocent. I want you for the same reason Lucy Littlewolf does, the same reason the entire fucking pack wants you. I want you because you're the most stunning, seductive, ravishing wolfgirl in the pack!"
Selena drank her sister's body in, knowing she was speaking the truth. Luna was a tall, svelte werewolf with a firm, round butt, curvy hips, long legs, a bushy tail, and six plump breasts that jiggled teasingly whenever she ran or even walked. Selena could feel her nipples hardening with each passing second.
Luna grinned wickedly. "You like my body, huh? Well, I guess I could let you worship it just this once." Luna lay down seductively in the grass, spreading her furry legs. "Come one, Lena! Be my bitch! Fuck me with your nasty, bald body!"
Selena nodded giddily and knelt over Luna. She began by worshipfully massaging Luna's titanic breasts, starting with the topmost and largest pair, a set of luscious E-cups, and working her way down to the bottom pair of perky C-cups. Selena squeezed them adoringly, loving the gelatinous feel of the six tits beneath her kneading fingers as she made her way to the sensitive nipples. It put a smile on Selena's face to know that soon these would be her boobs rather than Luna's.
"Uhhhhhhhhhgh," Luna sighed. "That feels so good! But enough foreplay, Lena. My poor pussy needs some attention."
Selena nodded and crawled on top of Luna, positioning her mouth over Luna's pussy, and her own pussy over Luna's snout. She shuddered as she felt Luna's whiskers tickling the lips of her wet pussy. Selena plunged her tongue into Luna's meaty lips, and the two began to 69 with primal glee. Selena groaned with lust as Luna's lupine tongue roughly lashed at her clit, setting its bundle of nerve endings on nigh orgasmic fire. The sisters fucked and fucked, Selena bouncing hornily on top of Luna's cushiony titties. Every second brought werewolf and human closer and closer to sweet release.
Suddenly, Selena felt it, and, going by Luna's violent twitching, she did too. Every nerve in Selena's body suddenly lit up, burning with intense orgasmic pleasure. She could see Luna's fur standing on end.
"Oh God, oh God, oh God!" Luna screamed before howling at the top of her lungs. She grabbed onto Selena with her shaggy arms, panting lustfully.
"AAAAAAAAHHHHHHHHHHHHHH!!!" Selena squealed as the orgasm surged through her, freezing her to the spot. As soon as she had recovered enough to move again, she studied Luna, looking for an opportune moment to cast the spell.
Luna weakened her embrace as she basked in her afterglow, and Selena saw her chance! She broke free from Luna's embrace, seized her sister's clawed hands in her own human ones, and began to chant. "Wolf thou art, but wolf no longer! Thy wolf is mine, to make me stronger!"
"What did you just—?" Luna started. Suddenly, she and Selena felt a surge of magic course through them.
Luna looked on in horror as two of her six breasts started to sink back into her body. "What the fuck?!" she gasped, clutching her paw as she watched morph into a human foot. "I didn't will myself to change!"
"No," Selena grinned, "I did." She sighed as she felt her own change beginning. Her bones audibly popped as her legs reshaped to be digitigrade and the beginnings of a tail began to poke out from above her ass.
"What the hell does that mean?!" Luna wailed, feeling her own tail sinking back into her as her wolf snout shank into a human nose and mouth. Her fur was fading fast, too, exposing vast patches of fair skin.
"It means I got fucking tired of being the token human in this pack and taking your shit all the time!" Selena growled, stroking her own fur as it grew in. "So I found someone who could help me shift AND get some revenge on you." She yelped in bliss as her nails sharpened into razor-like claws and her muzzle and extra boobs began to push out.
"I didn't fucking deserve THIS!!!" Luna wept as her changes finished, leaving her nothing but a fair-skinned human with a light dusting of freckles on her nose and long red curls. She tried in vain to shift back to her wolf form, sobbing when she failed.
Selena stood up, testing her now firmer muscles. She pawed at her fully transformed body, feeling every claw, teat, and strand of silver fur. She was perfect!
Luna sniffled. "What the hell am I gonna do?! If I go back to the pack, they're gonna lose their fucking shit! Especially Mom and Dad. There's a huge chance their even boot my furless ass out of the pack! And even if they let me stay, it's not gonna be like it was before. I'll be the omega, the one everybody orders around and trash-talks. Nobody'll wanna mate with me. I'll be... like you were. Sorry about that, I guess. I didn't get what it was like to live this. It sucks! What can I fucking do, Lena?!"