Alan kissed Joy. "I can't believe you did that," he said. "This is it for us. We only have one night more."
"I had to do it, Alan!" exclaimed Joy. "We can't stay like this. It's not how it's supposed to be. It breaks my heart to do this but it'll all be over and we'll just feel embarrassed about it."
"Joy,,," said Alan. "We have one night. How about it? Your bed's right here. It's our very last chance after what you just wished."
"I... of course I want it." Joy kissed Alan back and they helped each other off with their clothes....
After they had sex, Joy was getting ready to sleep. Alan put his clothes on, picked up the stone and said "I wish that when I go home, nobody will notice that I got home late and nobody would figure out that we had sex now." He prepared to leave and hesitated. He didn't want to lose Joy but there was no choice. Wishes couldn't be reversed; he couldn't wish that they'd be in love for any reason other than a love potion. It might be possible to wish something after they weren't in love but by then he'd no longer want to, of course.
Then he got an idea. "I wish...."
