The flask came loose from both their grasps and fell to the ground with a crash, spilling the liquid all over Jon. He gasped as the potion worked its magic.
First, his body changed, going from male to female. His hair got longer; his body became more shapely; the hair on his chest, arms, and legs disappeared; his hands and feet became more dainty. Yes, he was definitely a girl now.
Then breasts began to form on his (now her) chest. But when they got up to a C-cup, they didn't stop growing. It was the potion. It caused a person's body to change gender and expand their breasts to a gargantuan size. And when Jon's new breasts stopped growing, they were an H-cup.
Jon looked down at herself. Her breasts were so large that they were ripping her T-shirt. "I'm a freak of nature!" Jon yelled, in shock.