Thats why you also do not see her face in the screenshot.
Thank you for answering that. My theory about a vibrating toy controlled by Aiden, and the question why Sophia is hiding behind her desk like that, could be more or less easily answered by looking at her facial expression. That's why I previously asked if her face is visible in the teaser. Because if Sophia is making an "OH FUCK!" face, it's very plausible that she got caught offguard by a vibrating toy, trying to hide behind her desk in a way that her students won't be able to see her reaction and the effects it has on her body in that moment.
Now, to take this theory even further, the squatting position and Sophia's hand between her legs (I think people said that's what she's doing?) could indicate that she's having an orgasm, about to squirt all over the place. Yeah...I know the chances of that happening are probably less than 1%, but the squatting position is kind of throwing me off. She wouldn't need to squat just to hide the pleasure from her students. Sophia could just duck down behind her desk, no need to spread her legs like that. Well, who are we kidding, though. This second part of my theory is only wild imagination and not going to happen, but a man can still have dreams, right?
Anyway, most theories people posted here are somewhat valid and could be explained in one way or another. Well, except for those thinking that she might be taking a dump behind her desk.