If you are writing about this specific project, consider these common Matryoshka themes:
Just as you find a smaller doll inside, a "sweet room" is often a place where personal treasures are tucked away in drawers or secret spots. If you are writing about this specific project,
"Tucked away in the layers of my own little world. 🪆 Welcome to my sweet room, where every corner tells a story hidden inside another." If you are writing about this specific project,
While a singular official "text" isn't standard, you can adapt these thematic descriptions for use in captions, fan-fiction, or personal creative projects: If you are writing about this specific project,
The outer doll is the room people see; the inner dolls are the private thoughts kept inside.