Simply explained premise that anger is understandable but not acceptable:

• Anger causes me more problems than benefits especially when any comes from someone else.
• If we can agree upon this then we can help the other out of their anger for our own sake.
• The way we learn to reduce our own anger is by explaining to the other what was going on when I got angry and why, and get feedback from the other. (apology or speech in defence)
• Agree that the other should agree and accept the explanation / apology before we move on and try again.