I've never heard of this. Is it from your workbook?

If it perhaps you could give us the couple of sentences before and after so we have more context.

Off the top of my head it may be referring to the act of opposite reactions.

Something like:
Figure out your emotion. Emotions can be complicated and confusing. Figuring out what you are feeling, for example anger, annoyance or frustration, is an important first step. Are underlying feelings of guilt or fear influencing your anger?
Ask yourself what action goes with that emotion. Aggression usually goes with anger. Aggression can be physical, verbal or indirect and passive.
Ask yourself ‘do I want to reduce my anger?’ It only makes sense to try to change those feelings you want to change.
Figure out what the opposite action is. The opposite of aggression is kindness or at the very least, decency. Putting yourself in someone else’s shoes and imaging their perspective is an effective way to change angry and aggressive thoughts into something kind or at least understanding.
Do the opposite action all the way. Throw yourself in to acting differently in both your actions and your thoughts. Acting differently, without thinking differently won’t work. You have to do both.