You want to see if you can make her a smaller size, but would prefer it if she wasn't away of it just yet. With beads of sweat and a ball in your throat, you point the wand at her and hope for the desired results.
You don't notice anything at first, but then you notice that her socks look a bit wrinkled. You look her over, and see that her shorts look like they're spreading out under her, and her tight white shirt is forming wrinkles and riding up the couch, as is her hair. The phone looks bigger in her hands, and the couch looks bigger.
It's almost as if everything else is just getting bigger at first, but it's soon obvious that she's the one getting smaller. Her socks are clumping and sliding off her feet, her shorts look bunched up and several sizes too big, and her shirt looks wrinkly with a neckhole spread out almost shoulder to shoulder.
The phone is becoming hard for her to hold, and it slips some. She looks surprised! Has she noticed that she's shrinking?