How to vent out your anger harmlessly which is caused by a idiot who I am forced to see everyday?

Long story short, there is this stupid who is irritating the shit out of me. He knows exactly where to trigger and does that smoothly and no matter how much I act calm in front of him to not make him enjoy the after drama, it's of no use since my head starts aching after a while due to controlling all that anger. And, I can't show it either. It backfires all the time and I even tried mocking but god, I am helpless. And, I can literally do nothing about it. And, I repeat nothing. I am accidentally redirecting this anger sometimes toward the ones who really care about me because the frustration is kinda piling up inside me with no means to let out and I don't want that to happen.