The stairwell

You follow Heather into the stairwell admiring the curves through her tight red uniform. You start climbing the stairs and realize the upskirt view, and her panties are becoming more loose every step; sliding down her round ass and now giving you more revealing flashes of her pussy. Your growing cock is uncomfortably squeezed by your pants every step.

You see the flourescently pink thong getting so loose now by the third floor you think they are going to fall off any moment.

You see the thong quickly slide down her thighs and fall to her ankles.

*Thud*

You hear as you see her trip against the stairs before your luggage tumbles down a few a few steps. She is laying on the steps in front of you, with her thong hanging off one of her ankles.