FZ-Calm has a unique feel that has few equivalents among other lubricants for speedcubes. Start by applying 3-4 drops to your puzzle and do a couple of solves to spread the lubricant around the cube. This will make your cube faster and smoother, but also give your speedcube a much more subdued and quieter sound level when you turn it. Compared to FZ-Rush, this variant gives your speedcube a slightly slower and more controllable feel, but the difference is not very big.
Due to the contents of FZ-Calm, it is important that you store the lubricant with the cap on when not in use. The lubricant is safe to touch the skin, but avoid ingestion.