When do we use our triceps?

Extend/stabilize arm: The triceps brachii muscle is located on the back of the upper arm, and is responsible for extension of the elbow to straighten the arm. It opposes the flexion action of the biceps & brachialis muscles. It stabilizes the elbow when the forearm and hand are used for fine movements such as writing. Exercises such as push ups, bench press, & military press work this muscle.

Extend the arm.: Triceps are used to straighten the arm.