mom arm
When you automatically throw your free arm across the body of the passenger in your car when you come to a quick, unexpected stop.
Sorry about the mom arm, I didn't realize that jack ass in front of us was stopping so quick.
Mom Arm
When your mom stops the car suddenly and try to protect you by putting her arm across your chest but she just ends up karate chopping you in the throat.
Friend: How did you end up in the hospital.
Me: I got the mom arm.
Me: I got the mom arm.
soccer mom arm
The arm, specifically the right arm, a mother (or other driver) uses to protect the person in the passenger seat when they slam on the brakes. This arm is quickly forced in front of the passenger to ensure they do not move the, roughly, three inches they would normally go forward during an abrupt stop.
Thank god she used the soccer mom arm or I would have flown into the windshield!
mom at arms
Having a great body but have saddle bag arms. From afar the illusion is the arms look buff. Widely used reference to Man-At-Arms from He-Man.
Did you end hook up with that cougar we saw at the bar? No bro, she was Mom At Arms!