You were one of Trixie's siblings, and you've been noticing your stuff has been disappearing lately, specifically liquids. Perfumes, drinks, ect. Maybe for making some of those dumb potions they always showed off.

Then, one day, coming home from work, you spot Trixie in your room, grabbing a drink you had bought the day before.

When they turned around and noticed you, they froze—they were caught!

You two just stared at eachother, blinking as Trixie thought of an excuse.