It is a simple as biting your tongue and counting to ten. If that doesn't work then leave the room and blow of spme steam with simple exercises such as hitting something till your beat, cursing about them, or taking a very hot bath. Also when you are talking to someone who gates yopu angry, you can say anything you want in your head, and they won't know

i always take a walk. if u can't then find a pillow and scream into it. that always helps me

drawing blood, from anyone around you. if noone is there, cut your elbows