it is slang referring to a current condition or situation that exists, usually pleasant.
We used to say, "Hey, don't mess up the cha-cha dude".
In this case the person did something to upset the applecart or cha-cha of someone else.
I have also heard, Go along with the cha-cha. Here it is like the word "program" as in go along with the program, or cha- cha.