Start with the trousers

You watch her for a moment longer, waiting for the perfect moment to strike.

She pulls out an armful of games and then stretches up to place them up on the top shelf. At that same moment you snap your fingers.

Suddenly the clasp gives out on her trousers, and they slip, almost instantly down to her knees, with her currently reaching up as well, her shirt has ridden up enough to give you a great view of the light green panties tightly hugging the curves of her arse.

She instantly lets out a gasp as she feels her exposure, her arms too full to do anything about it, and she starts glancing over her shoulder, looking directly at the pimply faced boy at the cash register who clearly can't see anything yet with a shelving unit between them.