The problem with topping a taco is that it falls always and stay to the side.
In the horizontal position, it is much more difficult to fill the tacos correctly.
So how to make it stay in the right position to fill it easily?
Here is a photo of the obvious little thing that you are going to adopt:
You can even put one on each side.
And if you want to make cute homemade tacos with a cute shape, here's how to do it.