My preference for liquid lip colors is for opaque ones, so I often shun lip glosses. The Dior Addict Fluid Sticks are marketed as lip gloss but I really like the formulation, staying power and feel of these. I chose Rieuse as it was one of the most opaque in the line up, but I was never able to get it to show its true color on my lips, even atop nude beige lip colors.
Recently I got the Obsessive Compulsive Cosmetics (OCC) Lip Tar in Memento. It’s a beautiful warm, light peachy pink on my lips, really like it. One day, on a whim, I layered Rieuse on top of Memento, and voila! Rieuse in all its glory! So, yes for layering liquid on liquid products (just wait a bit for the first layer to settle).
Incidentally, the whole OCC Lip Tar line in the old, squeeze tube packaging is being discounted online at Sephora, as the packaging is being replaced. They are great value at $9 for 10ml, grab what you can of the few left.