The phrase "to know the trigger" means to understand the thing or situation that causes a specific reaction or response. It refers to being aware of what sets off certain emotions or behaviors in yourself or others. Full definition
Knowing your triggers helps you be better prepared and highlights some areas to focus on addressing as you continue through the divorce process. (mainlinedivorcemediator.com)
If you want to stop yelling at your kids, you have to first know your triggers and understand when you are more likely to yell. (whattheflicka.com)
I think knowing your triggers / weaknesses and budgeting are key — that's what usually keeps me on track. (theadoredlife.com)