Use your itching powder to make Sabrina take a shower

Time for a bit of ingenuity. You go to the kitchen and grab an ice cube, then a bit of string from the board room.

You tie your slime ball/itching powder to the string and the string to the cube. While Sabrina is resting her eyes, you lodge the ice cube in-between the branches on top of her. Now, all you have to is wait for it to melt…

With the cube dissolved, the contents of the itching powder bag are emptied all over Sabrina. At first, she doesn´t seem phased, but then it starts. A quick scratch on the nose and belly, it ramps up the intensity. The blonde digs deep into her shirt and rubs her finger all over her torso.

“W-what´s going on? Did I swim on poison ivy or something? I need a shower! Fast!” Your rival runs to the showers, scratching herself the whole way. Success! Time for step 2.