That's when you felt something poke your tail. It felt familiar. Then you felt it rub against your wet vagina and that left no doubt about what it was. Your eyes went wide. Amy still looked the same, the same feminine face and long hair, the same beautiful breasts and smooth skin. Yet some unmistakably also had something new.
"Amy...why do you have a penis?"
Amy blushed. "I accidentally transformed this morning too. I was taking my shower and I thought of you. I started to pleasure myself, but then as much as I was turned on by the thought of us being mermaids again together I started thinking about your penis. And I started fantasizing about what it would be like to have one. The next thing I knew I grew a dick. I had so much fun playing with it. When I finally got done, finished my shower, and dried off I went back to being a normal human girl. But I hoped it would come back the next time we were together."
"I thought you wanted to be a lesbian mermaid?"
"I did. I...I guess I learned something new about my sexuality today. But I don't want to become a man. I just want to...experiment." She added a devilish grin and you felt her penis rub against your vagina. "Don't you want to find out what it's like?"