Photoshoper here, that thing is a handheld keyboard. Basically it's a keyboard but only has 4 buttons instead of 100+ buttons like a common PC keyboard does. The reason behind this is because Adobe Photoshop, GIMP and many image editing programs make use of Ctrl as Alternative function for a tool, Shift as Reverse function for a tool and Z as Zoom tool. So we end up using those buttons the most. For artists who only have to draw, having a full size keyboard is space-consuming and useless so they only buy handheld keyboards like that one. Megumi probably used some tools that require her to press Ctrl repeatedly, so she end up increasing the vibrator speed. MC integrated the vibrator controller functions to the keyboard, so Megu's keyboard doesnt have High Low On Off like MC's one. Megu wore an isolated headphone, and isolated headphones work by omitting an opposite soundwave to the enviroment soundwave coming to your ear, in order to negate it. Which means isolated headphones dont have volume or any kind of remote controller. It is not nonsense at all.