A room temperature squash ball is surprisingly lifeless. Even blue dot beginners’ balls will hardly bounce at all. Warming them up makes them much more lively. You don't generate enough warmth with your hands to heat them up sufficiently, so usually this is done by hitting them up and down the court a few minutes. It'll do a good job of warming you up, too! Individual squash ball warmers are available, and some clubs provide wall-mounted devices that you can use while waiting for your court.