My first introduction to vtubing was reading articles about thots seething at Melody making money by showing off her body but not really. I recall thinking it was hilarious. I'm aware of her PL but this is the first time trying to watch a stream of hers like this and... this is something else. Apparently this device was designed or drawn by Froot somehow. Filian has called it an "adult booster seat." Do not open this spoiler if you value your sanity.
E: @Short I beg you cease.
It's not all that surprising as far as sex toys or mounts go honestly. It's easier on the body to use an elevated mount as well.