Your girlfriend has a naughty secret. She can grow any part of her body after she ingests cum, and she wants a lot of it to make herself bigger and better.
Your girlfriend brings home a size-exchange pen and uses it to shrink you and grow herself. How small will she make you? More worryingly, how big will she get? She's getting pretty close to the ceiling already!
Jemma is your girlfriend, and you have a present for her, a potion that will let her entirely control her body. She can use this to produce a growth hormone and grow herself bigger and bigger, beyond what you could ever imagine!
