Just breathe and stay calm. Usually remind myself that getting mad at a virtual loss is pathetic and I'm probably not gonna acheive greater things in life being upset over childish things.
I just keep my anger to myself. But when i cant stand it, i just rage on the mic thats all. Its not like i have anger management issues though. Im not Autistic.
Usually I just call up some friends and most of the times talking to them helps alot but if you have no one to call then go to Google and look for a discord group called "Patch Gaming" they have alot of members who help people with mental issues or need anger management also do not stop yourself from joining if you feel suicidal they have experts there aswell who can seriously help you