Responses

Because it's normal in that theme. BTW, only females (or female roles) goes into "Heat". Males goes into "Rut". And since Beastmen have animal characteristics, of course they would have mating periods. So, it's normal to have smut. Otherwise, they more human than Beastmen. (Omegaverse is similar)
Actually male cats IRL are capable of mating at any time, in response to a female's pheromones. Female cat can go into heat every two to three weeks during her breeding season. Male cats would always be ready for action
i feel like every time we get a beastman romance, it's always a type of animal that goes into heat