Her apron is gone

"No... no..." Sandry felt the breeze around her as her apron, snagged on the easel, was torn off her and left her standing in the middle of the room in her underwear and her gaping open bra, and rapidly gaining the class' attention.

"Sandry?" The teacher was looking at her wide-eyed, "What's going on here?"

As Sandry struggled for an excuse, Robyn stepped forwards.

"Sandry is helping me with my project." She said, "She's modelling for me, so obviously she has to be undressed."

"I see." The teacher nodded, "Down to her underwear, or completely nude?"