This piece can just be taped to the cover the eject button of the Xbox 360 Slim.

It prevents accidental presses while still allowing you to press it intentionally.

This piece addresses a design flaw of the Xbox 360 Slim where the eject button is like a touch sensor that too easily gets pressed and turns on the entire system accidentally.
This very thing happens to me a lot especially when putting a cover over my system to protect from dust when it is turned off.