You look nervously at Lydia. The wording of your wish had been too open ended and you could tell Lydia was uncomfortable with this.
"Will whatever wish I make override my first wish?" you ask.
"Yes" says the genie.
"If it still doesn't work out the way we want can Lydia rub your lamp and make a wish of her own?"
"After your wishes have been granted, the lamp will vanish from this place and reappear some other time and place. Otherwise, two people could abuse the lamp by passing the lamp between them, alternating wishes."
"Wishes?" asks Lydia. "I thought you said you granted only one wish?"
"Very observant, young lady. Your boyfriend was the one who rubbed the lamp but you were both present and both summoned me. You each recieve one wish and both must be given before either takes effect. Use them wisely."
"I still want to be able to change into a mermaid, but I want to be able to control it" says Lydia. "I don't want it to be controlled by my boyfriend's desires, hiding from my parents, and unable to swim in public. And no offense" she says as she takes your hand and looks deep into your eyes "if something doesn't work out I want to keep this is for myself."
"No, you're completely right Lydia. I don't want to ever lose you but I don't want to control your life. And if it doesn't work out I don't want to change someone else against their wishes. I should've been more careful. We just have to word this right. Do we even need the second wish?"