She grabs the curtain and loses her balance.

Ralli's sense for danger told her that the closest thing she could grab, the curtain drawstring, was trouble. Therefore, she defaulted to the only other thing in range. She chose the curtain ahead of her... but to reach it, she had to lean past Harley. Her own tongue shot out lewdly as she felt Harley unexpectedly manage to brush the perfect spot during the movement-

With a shout, the sergeant grabbed the curtain and yanked them down, causing the entire frame to collapse around them in a silky pile. Ralli herself fell over onto Harley, feeling the girl bounce roughly against the floor and beneath her teacher's weight. It would have been nice if the entire canopy had fallen in a way that would cover their shame and allow Ralli to collect her thoughts...

... Instead, Ralli was left pulling curtains off of her head as her naked, scarred ass and legs were left visible, with Harley's scrawny clothed legs and arms sprawled out beneath her.

The entire class was helpless to avoid laughing at this sight, even before most of them pieced together what was going on. "Oh Geod!" Liam laughed loudest, pointing and guffawing as his eyes locked on the dark behind more than anything else. "Is that your ass, Teach? Wh-who is that unfortunate soul underneath you? Gahahaahaaa!"

_"Crap," Ralli thought simply, keeping herself hidden while trying to think of the correct move. "I need to think carefully. Certainly, the class somewhat understands what is going on now, but they do not seem to know Harley is the one collapsed beneath me. If I want to, I can still protect her dignity. Then again... I admit I am considering getting back at her for playing such a dirty trick on me," the demon admitted, pouting beneath the bundle of curtains. "Ah... there is another matter to consider. I do not sense awareness from Harley. It is reasonable to believe she has been knocked ****. Whatever else happens, I should probably wrap this up and get her to the infirmary..."_