"In you get." Joyce reached out and grabbing Xander by the shirt pulled him into her home, keeping her grip on his shirt she man handled him to the couch in the living room and forced him to sit down on the sofa. Sitting down next to him she caught Xander's eye and keeping eye contact said, "Explain."
"Imagine I was able to make a wish and this wish could make you healthy." Xander answered.
"I thought wishes were bad."
"Um, yeah, they are. Buuuut this isn't a wish. This is like a wish. This is kinda like Willow's stupid make things happen spell she cast that made Giles blind, Buffy marry Spike and nearly killed me."
"The what? Buffy married Spike?" Joyce asked in alarm.
Xander tried to figure out how to explain and finally with a sigh said,"Uh, it was a magical misadventure and things were put right before anything permanent happened. Buffy never married Spike"
"Good. My daughter can do better than a vampire." Joyce nodded her head authoritatively.
"Preaching to the choir. Buffy can do better than a vampire, A-Men." Xander raised his hands and waggled them in agreement. Dropping his hands he shared a smile with Joyce. When Joyce continued to stare at him Xander remembered why he was here in the first place. Snapping his fingers Xander leaned back and gave Joyce a once over as he tried to figure out how to phrase what he wanted to say. "Do you want to chance my not-a-wish wish?"
"Xander, wish not wish away."
Clearing his throat Xander leaned in, "Okay, listen up, Joyce Summers is in perfect health, no brain troubles ever... and has the body of a twenty year old cross fit athlete."
With widening eyes Xander watched as Joyce's body changed before his very eyes, shrinking in some places, growing in others, firming, tightening, rejuvenating itself. He couldn't help but whimper "Holy Guacamole."
"Did it work?" Joyce asked looking from herself to Xander, "Is something supposed to happen?"
"You don't notice anyting different?" Xander asked amazed, when Joyce shook her head he quirked an eyebrow in puzzlement then added, "Joyce Summers is aware of the change that just happened to her body."
"OH MY GOD!" Joyce yelped as she jumped up and began feeling her body with her hands, "What? How? I don't.... How? Xander!" With a ear piercing squeal she jumped on the young man and hugged him to her, "I'm young!"
"You feel okay?" Xander asked, his voice muffled by being buried in Joyce's chest.
"Xander!" Joyce pushed the boy back and smiled at him, "I'm... I... You... Thank You!" Grabbing him up again she hugged his head to her chest again. The elation didn't prevent her from noticing that something was different about the situation than she was used to. Pushing Xander back just a bit she looked down between them and confirmed what she had innately know. "Xander? Where did my breasts go?"
"Uh..." Xander looked at the chest before him and flushed as he noticed that this new, buffer more muscular Joyce was perhaps a bit less blessed boob wise. "I think there was a trade off. Being in shape means less boobs?" He winced and drew his head back, "Don't hurt me."
"Xander I'm in the best shape of my life. Ever." Joyce Raised and arm and flexed showing off her new bicep, "Look, actual muscle." Joyce chuffed. "My head doesn't hurt for the first time in months. I think my health for a couple of cups sizes is an acceptable trade off. Am I younger?"
"Ummmm yeah?" Xander nodded his head. He smiled as Joyce let out a shriek and bounced up and down in excitement. On top of him. Which did interesting things to his unmentionables. When Joyce calmed down Xander mused, "I can fix the breast thing."
"Oh, really?" Joyce raised an eyebrow.
Xander couldn't help but smirk, "Your 'not a wish' is my command."