One potent way to stop your cat from meowing is by installing a Feliway diffuser in your cat's environment before it comes into heat. This synthetic feline pheromone surrounds your cat with familiar and safe scents. Pheromones are chemical messengers like the pheromones a queen gives off to signal to a male cat that she's in heat and ready to mate. The perk of the ones in Feliway is that they may have a soothing and calming impact on her.