Option 1: Rose Potter and the Ritual of Obliviousness

The next few minutes found Rose grasping the kitchen counter for support as Lily buried her face between her quivering legs, the MILF showing her daughter exactly why the younger woman was currently the second biggest slut in the Potter family. "Morgana's tits, Mum," she gasped, "why d-did you never do this beffffffoooooooooooOOOOOOOOOOOOHHH FUCK!" Rose's eyelids fluttered in pleasure as Lily's tongue seemed to grow a few inches longer so the older witch could slurp up the last dregs of cum that hadn't made it to Rose's womb.

"Get up on the table," Lily punctuated her command with a slap that made Rose's big, bubbly asscheeks jiggle, then vanished the table's contents with a gesture and climbed up onto it herself. Rose looked at her mother - legs spread and miming two girls scissoring with her fingers - and grinned as she followed her up. Both women gasped in delight as their puffy, wet pussy lips pressed together softly, a sensation neither had felt since the night after Rose's eighteenth birthday a couple of months prior.

"R-Repeat after me, honey," Lily gasped as the pair began to roll their hips, grinding their slick slits against each other, "I, Lily Evans, am an unfaithful woman..." The tabletop began to glow softly as Lily's voice gained an odd timbre, revealing the ritual circle that had been painstakingly cut into the wood and filled with magically powerful herbs and powders. "...a slattern, a whore. Those men who seek to keep me, those who I have pledged my life to, are blind to my nature. I have deceived them, and do deceive them, and shall deceive them ever thus. Let the scales cover their eyes forever, let chance confound them, let consequence never lead them to me!"

"Now you, honey," Lily moaned, her voice returning to normal as strands of her hair began to shimmer with light and the air of the kitchen around them hummed with energy. Rose licked her lips. "I, Rose Potter," she began, before the strange urge to push the rules, to bend and break them, took hold of her at the worst possible time, "am a cheating bitch..." Lily gasped, but couldn't bring herself to act now that the ritual was in full swing and any attempt to stop her daughter might make the results of her disobedience even worse. "...a slut, a fucking cum-addict!" Rose's voice seemed to thrum in her throat, her words spoken in the same unnatural tone as Lily's had been. "My pathetic, pin-dick relatives are soooo fucking stupid! They never realise what I am, and they never will! God, I hope they never figure out what a nasty nympho skank I am - even when it's right in front of them!"

"Nngh... Rose Potter, when this ends I'm going to-!" What, exactly, Lily Potter would do to punish her disobedient daughter would never be revealed. Light blazed from the runic symbols carved into the table, the girls' eyes and their suddenly-open, silently-screaming mouths in equal measure. Rose's last thought as her head lolled back and she and her mother slipped into unconsciousness on the tabletop was that the sight of her curves in the mirror hanging in the wall looked a little more natural - and Lily's a little more fake.

James Potter swept out of the fireplace and into the kitchen in a flash of green fire and the scent of charcoal. He paid no mind to his naked daughter on her hands and knees on the table, one hand reaching back to plunge a foot or more of girthy purple silicone into her dripping cunt. Instead, he walked up to his equally naked wife and leaned in to kiss her - and ignored the way she blocked him with an upraised palm. "Harry's staying another night with the Weasleys," he explained, "I decided to get home before Arthur pulled me into another discussion about plugs." Lily hummed disinterestedly, rubbing her pussy to the sight of their daughter masturbating in the middle of the kitchen. After James had bid them good night and left for bed, Lily wiped the hand he'd kissed on the countertop and turned to Rose. "I'd spank you raw for what you did," she noted, "if I didn't know it'd make you cum, you little tart."

"Mmm... You've said that twice now, Mum," the black-haired girl replied, conjuring one of the dishcloths into another dildo and summoning it so she could stuff her asshole. "You want to go out? We could toast our new freedom with a bucket of cum each."

"Maybe tomorrow," the redhead demurred, "I wanted to wait until your brother got home, make it really special..."

OPTION 1: The Potter women are hosting a party! And if all of the guests are burly, hung men... well, that's just a coincidence, surely! And if Rose and Lily's idea of entertainment involves getting dressed up in slutty costumes and dancing for them, before getting gangbanged and covered in cum... well, that's just being good hostesses! And if, after all's said and done, they see the guests off with open invitations to return and remarks about how superior they are to the 'men' of the house... well, I'm sure Harry and James will rationalise it all away somehow.

OPTION 2: Molly and Ginny Weasley [Ginny and Luna Lovegood having been aged up further to the same age as the Potter twins] are going to be meeting them later in a little-known shopping district known as Carn Alley, to buy some 'specialist' Hogwarts supplies to make their first year experience as fulfilling as possible. Lily, being the charms mistress she is, makes sure that she and Rose test each piece thoroughly before buying to ensure their quality.

OPTION 3: As a staff member at Hogwarts (specifically, the Charms professor), Lily has been asked to lead a muggleborn named Hermione Granger through her first visit to Diagon Alley and managed to get Rose allowed along for the trip, giving them an opportunity to show the girl how the Wizarding World really works (and how much more shameless Rose's interference with the ritual has made the pair of them).

OPTION 4: Something else! Feel free to write suggestions in the chapter comments, if you have an idea but don't feel confident that you can write it.