Lazy glutes - came across a helpful tip

I am doing FB Reach at the moment with some extra videos sprinkled in. It got me thinking about "improving" my glutes and other lower body muscles. There was also another post recently about lazy glutes and I got sucked into a googling frenzy. What exactly are lazy glutes? Do I have them?

Anyway, I came across something that mentioned the belt line test. If you wear a belt, or imagine yourself wearing a belt, how would it fall? If the front of the belt is angled down, this could be a sign of lazy glutes. If the belt is parallel to the floor, this could be a sign of activated glutes. I checked a mirror and I seem to default to more of an angled down "belt". I engage my glutes and shift my hips a bit and I get that parallel "belt".

I find this actually feels better on my lower back, my butt looks rounder, and I feel like it just creates such better posture for myself with such a simple movement.

I don't know if this is actually a good "test" for lazy glutes, but it seems to work and feel great for my body.