Peter would never have used the Master PC to change MJ, but Phoebe on the other hand was not Peter anymore. The changes she had given herself with the Master PC altered her mind and personality resulting in an entirely new person, though one that still had Peter's old memories and desires. Phoebe Parker was the kind of woman who wouldn't take no as answer when it came to her desires. Her desire right now was Mary-Jane.
Deciding the easiest explanation to a now changed Peter was magic, Phoebe typed the first of the changes she would need to make. A Spider-Totem had resurfaced, and irreparably changed Peter into Phoebe. The world adapted and the public at large didn't mind yet another person calling them self Spider-Woman. S.H.I.E.L.D. handled the identity switch for her personal life, Aunt May panicked but accepted it, and Mary-Jane maintained her love for the former Peter.
The next change Phoebe had to make was how she gained her symbiotic lover. Shortly into her new career, she discovered an A.I.M. lab that had obtained samples of the Venom and Carnage symbiotes, copied and merged them into one being. Phoebe raided the lab to stop the experiment, and in the process was exposed to the symbiote and accepted the bond. The hero community cautiously accepted it as Phoebe did not show violent tendencies, and the public took it as just a costume change. They still called her Spider-Woman; Depravity was her private pet name for herself. Mary-Jane however, was furious and stormed out due to her fear of symbiotes.
The last change was the big one. Phoebe took a deep breath and prepared herself for the big edit to her wife. She made it so the symbiote fear would over time develop into a curiosity about why Phoebe would willingly accept a new bond with a symbiote. As more time went on, MJ became increasingly driven to answer this question, and she was on her way to the apartment to finally get that answer.
Depravity smiled as she looked over her work, made sure she would remember both how things used to be and how they were now. She saved the changes, closed the laptop, and made her way to the couch the lay down. As she went, Depravity willed her lover to shift it's appearance to normal clothes, as she didn't want to scare off her precious MJ right away. The symbiote squirmed around becoming a black pair of jeans and red tank top, both gripping wonderfully tight around Phoebe, and she shuddered in delight at the feeling.
"This will be perfect! I can't wait for her to arrive!"
"Queen-Phoebe. Will work?"
"It will take a little bit of effort, but between MJ's new curiosity for your kind and the pheromones you gave me, I don't think we will have any problem at all." Phoebe ended her statement with a bit of playfulness in her voice.
Just then there was a knock on the door, Phoebe shot up from couch and happily rushed to the door. She swung it open and her face lit up upon seeing Mary-Jane again. She hugged MJ tightly and began to let out the pheromones so they could do their work.
"I thought you would never come back! I missed you so so much after what happened. I'm glad you decided to see me again!"
"Pe... Phoebe, I'll be quick about this," MJ said, breaking out of the hug "I'm happy to see you too, and even happier to see you haven't become a raving lunatic with that thing on you. I'm not back for good, I just need to know why you would ever let one of those things on you again."
Phoebe pulled back and looked at her with a pout. "Mary-Jane, there is no quick answer for that. Please come in and we can talk things over."
MJ frowned and begrudgingly accepted, "Alright, but I'm bolting the moment that thing takes control of you"
Phoebe made her way to the couch and sat down. "It's not going to control me," she said with some annoyance in her voice "It's entirely different from Venom and Carnage, we're equal partners in the bond." She patted the spot next to her so MJ would actually come over and sit.
Mary-Jane reluctantly moved over to the couch and began. "So what makes you so accepting of this one?" She was starting to feel slightly warm.
Phoebe began describing how the bond felt. The symbiote material was amazingly comfortable, she was full of energy and never tired, and there was a wholeness she had never felt before. As Phoebe continued to talk, MJ fell further under the influence of the pheromones and entered a sort of daze where she was just accepting what Phoebe said. Phoebe continued on, commenting about an unlimited wardrobe, which they both giggled over. After about half an hour of Phoebe controlling the conversation, MJ was snapped out of her trance by what her former husband, now wife, just said.
"...and the sex is best experience you'll have in your life!" Phoebe grinned at Mary-Jane.
"Excuse me?!" MJ could not believe what she had just heard. "You can't be serious on that!" She also at that point became aware of just how horny she had become over the course of the conversation. She loved Phoebe, and being near her again was making MJ increasingly hot and bothered. With the mention of sex, that almost tipped her over the edge.
"I entirely am. Its mind-blowing, and honestly puts the word orgasmic to shame." MJ blushed at that comment, surprised at how forward Phoebe was being. "I never felt anything close to that before my new bond."
Mary-Jane couldn't take it anymore, she was at her limit and felt so much heat down in her groin. "Let me see you in the suit. I know you've got it hidden, but change it back to normal."
Phoebe was ecstatic, her plan was working and Mary-Jane was coming around to the idea of symbiotes! She hopped up from the couch and posed in front of MJ. She willed her lover to return to normal and let out a moan as her clothes liquefied and spread back over her body. As the material closed around her head, the moan ended distorted and monstrous.
Mary-Jane was at the edge, she wanted to jump on Phoebe so much, but she was still held back by lingering fear. "Phoebe, how do I know the sex you talk about isn't how that thing is controlling you?" She barely managed to say without sounding too aroused.
Depravity let the lower half of her mask melt away to reveal her human jaw. "You don't" the being playfully said with a smirk, "until you try it for yourself."
"I can't! No! No, no, no, there's no way!" MJ stammered out in a panic
"Aww come on Mary-Jane," Depravity reformed her full mask and her voice became distorted "Why not join me in some depravity and see how one of these feel? What is the harm in a little indulgence?"