Yank!

You give a good pull, and the pants take their natural course downward, pooling in a heap on top of her boots at the bottom of her shins.

She feels what just happened and freezes in surprise, giving you a moment to appreciate your work. She wore underwear of the same type of fabric and style as her bra, black, but also a black garterbelt suspending her stockings. She must be regretting that the garter couldn't have held up her pants too though.