She didnt want it to stop

Her huge female cock had already grown so big, and she finally was able to cum, but she didn't want it to stop, she wanted more growth. Her desires soon took her mind, and because of this, her dick started to grow larger, soon begining to break the roof of their house.

Adam has never seen anyting like it, and he was amazed at how big she was getting. It had btoken their roof entirely by now, and it was only getting bigger from here.

Her penis had far surpassed her brother's, and it was still growing. Soon, her dick had began to destroy the buildings under it, as it was still hanging from the host of such a massive erection.

Adam didn't want to feel left out, but he felt that he couldn't do much about his own boner. Whether he should take the risk of drinking more "growth X" is up to him, but those desires would most likely lead to the world's destruction. As if his sister hadn't already gone down that path though, because her dick was still growing more and more.