You decide to become a young adult female. Sure you were a guy before this happened, but one look at her makes you more then a little curious about the other gender. You grin and put your paw on the young adult then on the female card. Tanya picks up the cards and looks them over.
"So you want to be a young adult female eh? An interesting choice for a young male. Alright, just let me get the proper potion" she says. She turns around and opens a small door of a cabinet and grabs a couple of vials and mixes them. With the mixture complete, she turns around and holds the vial close to your mouth.
"There we go, I'll tilt it up and you drink it. Ready?" she asks. You nod your head and open your mouth, she gently pours the contents of the vial into in and you close your mouth and swallow it. It was a sweet honey like taste to it.
The otter girl picks you up and puts you on the ground. Your changes begin almost instantly and you feel a strong desire to lay on your back. The otter girl helps you to roll over even as you already start to gain mass. Where the mass comes from, you have no idea, but you really don't worry about it. Your legs get longer and your torso gets wider. Your forelegs start growing and you look at your forepaws, the webbing in them is receding into your digits and the paws are getting bigger!
You are now about the size of the otter girl and you are still growing. Your tail adjusts it's shape and you feel a desire to stand up. When you do, your tail's length decreases such that it's not quite as long relative to the rest of your body and points backward and down at an angle rather then straight down. Your hips adjust their shape and size into a shape that looks more feminine and you feel a strange tingling on your chest.
As your legs and arms length stabilizes at a normal human like length, you stop growing and seem to be about 5'8. The tingling in your chest continues and a pair of nipples suddenly appear near the top of your chest, they quickly protrude as a pressure builds from under them. Right before your eyes, the pressure result in a pair of little breasts appearing on your chest and they don't stay little for long. They get bigger and bigger and bigger! As their growth subsides, you cup them gently. You guess that they must be at least 'c' cup sized. The final stage of the transformation manifests itself as your manhood tingles and shrinking until it was completely absorbed into your body, leaving behind a cut little slit.
Now a young a very beautiful otter woman, you stand there simply staring at your body before Tanya asked you what you think.
"Wow, this is very nice" you sheepishly say.
"So what would you like to do now?" she asks.