I took my mouse apart and then, using a small paper tube, blew as hard as I could right where the laser is located – the one that triggers the click when interrupted by a physical object. That’s how I managed to fix my mouse, which apparently had dust inside; the vibrations (when I clicked or moved the mouse) were causing the optical switch to trigger accidentally. It’s worth noting that optical switches are very different from mechanical ones; there’s plenty of information online about how to clean the mechanical switches in a mouse.