Later that day, when Kristen had taken you off to bathe, you met up with Mai who was hanging out at Kristen's house. It was more Mai sneaking into the bathroom and grabbing you off the pile of clothes, but that's not as important.
"Alright diaper, I don't care who you are, we're, whatever. Nor am I upset or anything. Instead, I want to male a deal with you. Can we talk?" She asks.
You focus on the gun and return your ability to speak, but keep yourself in diaper form. "I guess we can... what do you want to say?"
"So you can talk, that makes things easier. Alright, so I want to swap places. You can have my body if you want, but I want to be Kristen's diaper."
"Not happening. Or that is what I would say. How about this, we swap back and forth each week. One week you are Mai, the next you are Kristen's diaper, then back to being Mai one week after that, and so on. How's that sound?"
"Deal. But I get to be the diaper next, and let's agree that we trade at midnight, on Sunday night. That way we start the first day of the week on a Monday. Also, as you now know, yes the two of us are in that kind of a relationship. DO NOT LET IT BECOME KNOWN! My parents are absolutely against that and will not hesitate to put distance between us if they suspect it. And lastly, you will not change out relationship dynamic. I am the Dom. She is my Sub. She always will be my Sub too. I will try teaching you how to do it right too, so no need to worry about that."
"Hmm, that's a fair deal. Could I modify your body?"
"Uhhh, I guess, but nothing too crazy alright? What did you have in mind anyways?"
"Adding on some tits."
"YOU CAN DO THAT?? Oh my god this is the best! I finally can have tits! 100% yes! Please give me tits. I am sick of being flat as a board. Make them nice and big too! Oh, now I can't decide if I want to be Mai's diaper or experience having big tits for the first time in my life."
"Well, how about I give you your tits, then we decide from there?"
"Please!"
"Just tell me when to stop growing them." You tune the gun once more and begin developing Mai's chest. Slowly but steadily pushing out her top as more and more breast tissue formed beneath her nipples. You had expected her to stop at around a C-cup, but she didn’t stop you until her slender upper body was holding up a pair of enormous H that were wider than her shoulders.
Now standing with a slight hunch forwards, Mai marveled at her new assets, almost coming to tears with happiness. Her once major flaw (in her mind) now was fixed. And to help her out, you made her body able to effortlessly support the new weight without causing any strain, soreness, stiffness or lasting difficulties. And you ensured they would keep their natural shape without sagging more over time as a bonus, since you were a co-owner of these tits too.
Mai hugged you tight to her new chest, then kissed your front, while also giving you a deep sniff which you chose to just ignore for now. There already was no mistaking the fact that Mai was as much of a perverted degenerate as you were, so it would be like the pot calling the kettle black if you were to comment about it. It's not like you haven't been doing the exact same thing the entire day after all. Partners in fetishes, stick together.
And so, with you and Mai quickly becoming co-lovers of Kristen's bodily scents, in addition to her in general, you began the plan with Mai deciding on taking over diaper duty for the remainder of the week.