We can't figure out this teapot but we want it

It's not sorcery but it's close enough to it.

Called 'The Assassin's Teapot', presumably because you could pour normal tea for yourself and then poisoned tea for your enemies back in the day, this teapot displayed by the people at Grand Illusions can pour milk and/or tea depending on where you hold it and even after its workings been explained we're still pretty baffled as to how it works. All we know is that we want one.

Via YouTube

Have you come across tea magic such as this before?