That's not all

"What the fuck..." Slytherin mutters, holding her shirt shut. "Have either of you got a pin or anything? Something to hold this thing closed?"

Gryffindor and Ravenclaw step out of the queue with Slytherin, and you watch as they each search their bags, finding nothing.

You sigh a little as the other two girls form a protective barrier between Slytherin and the queue, but at least with your powers you can still see as Slytherin pulls open her shirt again, using the corners to tie it closed, revealing the expanse of her stomach, as well as a good portion of her bra at the top.

"There'll be cosplayers in less right?" Slytherin laughs, getting chuckles from the other two as well. They sound far too happy for your liking.

With a click of your fingers a sudden wind picks up and whips around the three girls, paying a good deal of attention to Slytherin's skirt, blowing it up and flashing you, and several passing boys, a good portion of her arse, only a thin black thong revealed underneath her skirt.

"Fuck!" Slytherin yells again, her hands moving down to smooth her skirt, suddenly beginning to worry about what is going on today.