With you asleep, Brooke decides the only course of action she can take now is to go back to the shop where the two of you bought the rings, and explain your dilemma to someone there. The thought of having to go into detail about what has happened to someone else is disconcerting for her, to say the least-- but there's no better alternative. Brooke cleans up again, being careful not to disturb you very much, and then gets dressed. She chooses a pair of semi-transparent lace panties and a skirt; normally she wouldn't be quite so bold with her choice of clothing, but she recalls how stuffy it was in your underwear when she was your penis, and figures it will probably be more comfortable for you. She grabs the magic items, including the gold ring, and takes them with her.
Within half an hour, she's back at the shop containing all the magical items. She stops at the counter and waits. Eventually, the same young Asian woman from before emerges from the back room and notices her. "Oh, hello again," she says, recognizing you. "You're back? Where is your boyfriend?"
"Uhhh," Brooke stalls. Discreetly, she mumbles, "He's... um... still between my legs..."
"Oh, I see," nods the shopkeeper with a sly smile. "It is his turn now. But then, why are you back here?"
"Because I have a little problem," says Brooke, holding up both of her ringless hands. "The gold ring you sold us came off my finger without him turning back."
The shopkeeper's smile fades as she realizes the severity of the situation. "Hmm... odd. That should not happen... I know the maker of that jewelry set very well. Her enchantments are usually fail-safe. I am terribly sorry about this. Would you like a refund?"
"All I want is for my boyfriend to not be a part of my body anymore," says Brooke, exasperated.
The shopkeeper nods apologetically, a bit embarrassed by the request. "Of course. I understand this is... a sensitive matter, but can you tell me what happened, specifically?"
Brooke gives the shopkeeper the ring to examine, and tells her all that had transpired before the problem arose-- the way that you had jerked her off, and swapped rings with her in her sleep, and how she had used the vibrator on you just before your mind started changing. When Brooke is all done telling her story, the shopkeeper excuses herself to the back room once more to make a phone call. From her place waiting at the counter, Brooke can faintly hear the shopkeeper's voice, but can't understand one word she says, as the conversation is in Mandarin Chinese.
At last, the shopkeeper emerges again, with a grim expression on her face. "I just contacted the maker of the jewelry set, and told her what you told me. She says you and your boyfriend have probably overexerted the rings. If he exchanged rings with you right after he was done climaxing with you, then one of you has been the other's genitalia for several hours straight, without much of a break between. The telepathic link created by the rings was very finely calibrated. They were not meant to be pushed quite so hard, with multiple different sources of erotic desire incessantly pulling them in different directions. The good news is, it can be fixed. Your boyfriend can be restored to normal."
"What's the bad news?" asks Brooke nervously.
The shopkeeper bows her head. "To do so, you will need a special custom piece of enchanted jewelry. The maker of this set lives in China, so it will have to be shipped here, and may take a few weeks."
Brooke can feel herself shaking. "Weeks?!? You mean he's stuck as my vagina until then?"
"Oh, no, you mustn't allow that," says the shopkeeper. "Didn't you read the warning I included with the set? Being another person's genitalia for longer than 12 hours at a time is very dangerous. From what you've told me, he has already experienced a personality shift. It is still early, so if he were turned back to normal now, he would mentally revert back to his old self, too. But if you allow him to stay in that state for longer than 12 hours at a time, the mental shift may become irreversible-- when you turn him back to a human, he will still think he is only a vagina."
"Wh-what, then?" asks Brooke. "What are you suggesting?"
"I can slightly alter the enchantment on your gold ring," said the shopkeeper. "It will not fix your problem, sadly. I do not have the power to do that. But it will provide you a temporary solution, until your custom item arrives. When you put the gold ring on your finger, you will be able to swap rings with him by saying a phrase of your choice. He will be back to normal, wearing the ring on his finger, and you will be his penis again, and he will have another 12 hour time limit before he must trade with you again."
"You can't be serious," replies Brooke. "You mean we have to keep switching places with each other for the next few weeks??"
"I am truly sorry," says the shopkeeper. "It is the only way that both of you will be able to eventually return to normal. I will call you as soon as the item arrives for you. In the meantime... not to diminish the seriousness of the problem, but... you could probably use this time to have some fun with each other. You have a while before this can be resolved."