She plunged the wet end of the vibrator between his lips, pushing hard to overcome his reluctance to open his mouth to it. It filled his mouth, stretching his jaws wide open.
"If you bite and leave teeth marks on it," she warned him, "I'll bite and leave teeth marks on yours."
She turned up the vibrating control. The buzzing seemed to go through his whole head. She held the control end firmly, keeping his head in position and pushing down with enough pressure to prevent him spitting it out. After watching him for a few seconds, she plunged the vibrator up and down a few times in his mouth.