Alice, Alex' older sister

Alice had been at a study group and had gotten caught up in traffic. Jason the neighbor's car was driving slowly ahead of her, but they were just a minute away from their houses so she didn't want to try and pass him.

As she got home, a message made a sound on her phone. "Hey, I got girl problems, you home soon?"

Alice sighed and went inside the house and called out loudly. "What's this I'm hearing about girl problems, Alex?"

"Why are you screaming?" a girly voice called from upstairs, causing Alice to pause before skipping up the stairs towards Alex' room.

Inside her brother's bedroom, she finds a weird sight. A fake blonde in a black dress tapping on her phone. "Who the hell are you?" she asked before looking around the room. "What the hell happened in here?"

"I said I was having girl problems," Alex said as she got up from her leather couch and did a twirl. "I'm your brother. in spirit... mostly. Oh, you've probably been stuck in the car doing karaoke on your way home. Newsflash: someone fucked with the rules of the universe, you can be transformed by horny desires, your own or others nearby."

Alice stepped back a step and lifted a finger for a pause. "That's... insane."

"What's insanity but a minority's dissenting opinion about reality?" Alex said and shrugged. "Here, I've been trying to master some minor transmutations," she said and closed her eyes and went silent. Within a second, her black dress morphed into a flowery hippie outfit, a pair of glasses manifested on her forehead, her hair grew longer, and her tits were suddenly on full display.

"Aha! That was fast!" Alex said, giggled and gave her sister the peace sign. "The world is made of love and peace!" she said in a Japanese accent before noticing she was flashing her sister. "Woops, well, at least you still got bigger tits than me."

"That's not a compliment from a boy," Alice said in curt reply, realizing this idiot with magical powers can't be anyone but her brother.

"Not much boy left in me I'm afraid," Alex said and sighed. "Met some woman in the corner shop by the train station who offered blowjobs by the soda shelves. I noped the fuck away, but before that she cursed me to become a girl with a kink for being an exhibitionist."

"Cursed you? You seem pleased as punch," Alice said, a hint of exasperation in her voice.

"Yeah, that's the shit isn't it. I was male until I got home, but on my way here I felt my preferences get overwritten," Alex said as she emoted holding the steering of her bike, rolling her shoulders and making a sheepish look on her face. "So I suspect I'm not going to be able to get horny and try to undo this change myself. And Jamie and Max are coming over soon and I'd hate... well, rational me would hate the idea of having them spit roast me and turn me into their personal cum dump."

"TMI, Alex," Alice said with a open palm against her, blushing at the scene in her head of Alex eagerly sucking and worshiping cock.

"Oh, sorry, I'm just a bit stressed and my new mind seems a bit more liberal about these things," Alex said and shrugged her shoulders. "Anyway, you think you could do me a favor and try to turn me back into your brother?"

"How the hell would I do that?" Alice asked, slightly overwhelmed. "by jerking off and imagining you as my brother? I don't know if I can get off on that."

"Fuck, I guess that's a fair point," Alex said and scratched her chin. "Maybe you could turn me into a step-brother or something, then I could probably get the rest of the way there myself?"

"Step brother porn? I dunno," Alice said with more doubt on her face. "Maybe I could 'get there' that way, but this is some weird shit you're asking of me!"

"Hey, I'm not disagreeing with you about that," Alex said and giggled, her sincerity doubtful in Alice eyes. "Look, I'm not sure how far reaching this effect is. Maybe if you go to the bathroom and I sit outside the door playing Wordle on my cell phone would leave you close enough to make it work?"

Alice gave Alex a exasperated look before slumping her back in surrender. Besides, she was beginning to feel a bit aroused for some reason. "Fine, I'll fap to try and turn you back," she said in a quiet voice.

"Yay!" Alex beamed, clapped and bounced eagerly, her free range titties bouncing eagerly on her chest. "I owe you big for this, sis!"

"Oh you have no idea!" Alice said and moved out towards the bathroom.