"I'd really like it if you were my vagina," said Haley. "I know it's a little personal, but it would really make me happy to have you as my pussy."
You think it over for a minute. You've always wanted to get into Haley's panties, but never could since she's a lesbian. Now, she's inviting you into her panties, albeit in a much more literal fashion than you had hoped.
"Ok, I'll do it. But if I really don't like it, I'll change back, OK?"
Haley's face lights up. "Great! Thank you sooo much! But how will you keep your ability to wish?"
After planning it out, you figure out how to word your wish so that you have an out. "I wish that I was Haley's vulva, vagina, and reproductive organs, but that I would retain my consciousness, all of my senses, my ability to communicate, and my ability to make wishes, and that I would keep this ring as a clit ring." You added that last bit because you didn't want to lose the ring when you transformed, plus having a pierced clit seemed kinky.
Immediately, you feel a twisting sensation as your world distorts and warps to accommodate the changes. Your body feels like jello. After a few seconds, the disorientation subsides, and you regain a sense of orientation. You are now facing downwards, with a sort of tarp pulled across your face. Your "mouth" is slightly open, and feels damp. You no longer have a tongue, but you can still taste your "saliva", which you guess is Haley's pussy juice. Yours, actually. You don't have any arms or legs, but you can sense a sort of "throat" and "stomach" further behind you, corresponding to your uterus and cervix. You find that you can flex your "lips" slightly; they are extremely sensitive, and rubbing them together makes you drool a bit. There's a tiny bit of you poking out, that feels like your old penis, but positioned where your nose was. You correctly guess that that's your clit. Satisfied with your inventory of your body for the moment, you try to communicate.
"Hey Haley! It worked! I'm your pussy!" you send out. You can't speak, but you feel like you can still "transmit" thoughts.
"Wow, Joey, is that really you? Try flexing your labia as a test." You do so, and you hear a muffled squeal from above.
"Wow, so I guess you're my pussy now... what would you like me to do? There's a lot of things that I'm eager for you to experience..."