Kago Mari is usually the type to tease and dominate masochistic men with her seductive personality, but this time she experiences the vibrator for the first time herself. A highlight is her surprised reaction right from the first shock—"So this is it!"—as she feels the sensation. True to the Challenge! Timer Vibrator series, she's bound in handcuffs with a penis-shaped attachment fixed onto the vibrator inside her, receiving relentless, randomly timed stimulation without pause. In the bonus footage recorded immediately after the main challenge, she performs vibrator masturbation while wearing an ultra-thin leotard, making the scene even more erotic.