Lua - set a function from a class

I am currently trying to learn how to bridge Lua with C++ and write scripts. The problem that I have is that most of the tutorial or documentation is somewhat simplified. Or maybe I have the wrong approach, which is why I am asking here now.

I am trying to initialize the meta table and more specifically. Trying to add functions. Like so;

luaL_Reg rmFuncs[] =
    {
        { "rotate", RotateBlocks },
        { NULL, NULL }
    };

But to add RotateBlocks is a bit tricky. All examples that I've found is done in main and not in classes. RotateBlocks is actually Application::RotateBlocks.

So the only way for me to make it work is like this:

static int RotateBlocks(lua_State* L);

Is this the only way? Because this causes a lot of problems. As it is static, I cant actually rotate the objects that I want inside the function. Because all my membervalues complain on the function being static.

So how do I actually do anything useful inside my functions and not just printf a random sentence as in all the tutorials or documentation?