Doing something when you should be doing the other, or doing something in the wrong order.
On a clock the sound is supposed to be "tick" "tock", "tick" "tock". If one does "tock" when they should be doing "tick" that means that person is doing something they should not be doing.
Example: Should be doing "A" instead of "B", But every time you do "B" when you should be doing "A" and doing "A" when you should be doing "B".