If the Vice Principal caught her she'd be in detention until she was old enough to retire, so the best course of action after falling through the ceiling was to hide under a desk. Your desk had been the closest, so she crammed herself under there as comfortably as she could and she listened as the Vice principal accused the others of causing a ruckus.

As you tried to deny any sort of ruckus an idea struck Illyana, she smirked as she carefully maneuvered her face to lightly nip at your knee. When she heard you squeal then attempt to cover it with a cough she grinned smugly, she did it again, this time going a bit lower to your calf, struggling to muffle a laugh as you and the other detention goers hid the noises that you made in response and tried explaining them away.

Once the coast was all clear she climbed out from under the desk, sitting on it and crossing her legs as if she'd done nothing wrong,"I hope you don't think I owe you all for keeping my presence a secret."She flashed you a wicked looking grin,"Isn't that right, Princess?"