This is the sequel to the critically acclaimed guide, "How to Left Click". If you haven't read it, stop, go and read it. The information that is about to be presented to you is dangerous, scary and will probably make you cry. It is only to be attempted by a master of left clicking. You have been warned.

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First thing I want you to do is to reach for your mouse with your dominant arm, just like when you left click.
Place the Palm of your hand on top like your cupping a potato. Make sure your Index and Pointer fingers are positioned on the Left and Right Triggers. You must avoid the temptation to left click, this is right clicking, it's a complete different skill.

Maneuverer the mouse to where you wish to click and apply firm and precise pressure to the Right Trigger of your mouse, using your Pointer finger this time. Release the pressure once your click is complete. Making Sure to rest your pointer finger above the right trigger once more.

Congratulations, you have successfully Right Clicked.
Troubleshooting:

I keep left clicking by accident.

Right clicking is a fairly advanced technique and it takes years to master, if you don't get it right the first time. Stop, throw your mouse away. You aren't the chosen one, and don't deserve to have a two-button mouse. Continuing might attract the rage of the council of the mice.