Placing Small Lever Into Mount

[SonOfLiberty796]

You can simply have an inactive working lever on top of the mount and have it set active when the lever collides with an area, preferably infront of the mount.

But then how would it be able to move up or down? It would just fall off (the lever on the mount). I tried that already and it just falls off. There is something else, which is the part I don't get.