"I want to be a Mermaid!" Sarah said.
"The most popular choice amongst women who join us!" The Doctor said with an approving nod with the head as he chose the proper syringe. "Now that we've got the right transformation syringe, we can begin the process!" The Doctor said. A nurse arrived with a device and a tank of seawater. "Now pay attention because this is important, this device will be entering your labia, clitoris and anal cavity. Once the inoculation takes effect the transformation will likely cause you to feel a sense of worry that you may lose your feminine organs. This device will allow them to remain but they will shift as well as several organs changing and when submerged in the water, your lungs will shift into a set of swim bladders and you will be able to breathe water. However the longer you stay a mermaid, it will be more likely that you will not remember your human past." The Doctor said.
Thinking momentarily Sarah simply said "Do it Doc!" The Doctor swabed Sarah's arm and injected the contents of the syringe into her.
Within moments the device finds their respective spaces and as Sarah achieve orgasm, her transformation happens as her legs merge into one mass, her B-Cup breasts grew to a C-Cup and scales cover her areolas and nipples. Her belly button disappears, her fins quickly emerged finishing her transformation. She breathed a sigh of relief as her orgasm based transformation ended. As she looked over her new form, she smiled and flapped her tail. However she felt a need to breathe. The Doctor and the nurse relaxed Sarah long enough to get her in the tank of saltwater. The Doctor and a small amount of people helped her into the pool with the other mermaids. As she awakened, she was greeted by a friendly face and taken to meet the others