To use le power of Lenny, you must first copy him. Select this and press Ctrl+C:
( ͡° ͜ʖ ͡°)
To unleash Lenny power, you must press Ctrl+V in a place you can type.

If you would like to use Lenny quickly on Gmod or Team Fortress 2, open the developer console. To do this, you must go to Options>Controls and press Advanced... then you press Enable developer console. Then press ` on the keyboard and then the developer console will show up. Type in the console:
You can replace / with any key you would like to use to unleash Lenny on your victims.

Thanks for reading this guide, and remember to brush your teeth and have swag.