“Ching chong” (by 1864) is a racist slur used in the English-speaking world to put down people from East Asia by mocking Chinese. Often it comes with other racist acts, like pushing someone off a playground slide – or burying them in a mine shaft.
It is not just ignorant, insensitive schoolchildren who say it. So do grown people in the US in the 2000s and 2010s. For example:”

 
See on abagond.wordpress.com