Try to warn her

"Mhmmmm!!!!" you scream into the gag and wiggle your body against the straps. However Mistress Elizabeth says "Good night, pet," and she leaves you alone in the room.

Bzzzzzzz!

The vibrator starts again, and you tense against the straps holding your body and the arms of the straitjacket. But in the end you give up, and you remain idle until the vibrations cease, and you can get some sleep again.