The wheels in Sarah's mind spun furiously. She could do anything she wanted with the rock in her hand. But she didn't want to do anything rash: she wanted to savor her new power. Her new control over Jon, and anyone who stood in her way.
Small changes. Piecemeal. Step by step. Things that Sarah could watch as they happen.
"I wish," Sarah said, "that every time Jon comes in physical contact with someone who is girlier than him, he takes on one of their girly traits. And I wish that any time Jon comes in physical contact with someone who is less girly than him, they take on one of his girly traits."
Sarah smirked her trademark smirk. She'd see how this played out before doing anything else. She could sit back and watch it work, or at any time she could step in and interfere with things.
She stuffed the rock into her bookbag and sat on Jon's bed waiting for him. She figured she'd give him a little jump-start.