Imagine: Mouse!Luka teasing Lady Noire
Mouse!Luka (let's call him Multibuck - "buck" for a male mouse) multiplies into smaller versions of himself, at first he'd used it in battle responsibly, like helping Mister Bug and Lady Noire fend off akumas and come up with tricky traps.
But he soon noticed the Mouse Miraculous' other effect.
It flustered Lady Noire to bits.
Since he knew she was secretly Marinette, he used it to his advantage, much to his amusement and her utter embarrassment.
Imagine hundreds of mini Multibuck's, all either on or around a red faced Lady Noire/Marinette, showering her with praise and compliments, some braiding the small strands of her hair, others praising her designs...etc.
Luka wasn't surprised when Ladybug gave him the snake miraculous the next time she needed assistance from another hero, and when asked why not the mouse, she was suspiciously silent, red faced, but silent.