To spray or not to spray - that is the question!

Dear George,
I am currently extremely stressed by my home situation and my human's behaviour. It has really upset me. She has brought home a new human, one who works in a veterinary clinic. Yes, one of those. A complete stranger to me. He smells of dogs, feline fear, vaccination needles and disinfectant (ironically smells a bit like cat pee). True, I have had a few scent hints about his presence in her life. She stayed out one night all night and came back looking very pleased with herself. As if the cat had got the cream, I might almost say. Now he has turned up and spent the night here. Yes, the whole night. He didn't even have the decency to mate and leave.
Shall I spray? I think it might make me feel better. And it would show her how very upset I am by her mating behaviour. What do you think? I rather thought I might do it on the unmade bed after he had got out of it.
Yours
Louis.

Dear Louis,
No wonder you are upset. The sex life of these humans is so outrageous. Any time. Any season. The females are ready for it all year round. Their permanent readiness is really disgusting to felines. We have proper seasons for it, interspersed with kitten bearing and usually we remain abstinent during the winter. Makes sense. Who wants to have kittens that die of cold. As a cat who has had the snip, I really feel sorry for them, at the mercy of their ever present hormones.
Spraying gives the message "Stop it." Or "Piss off". Or both messages at the same time. However, it is the nuclear option for us cats, Louis. It is the ultimate weapon and the final deterrent. It can go wrong. Humans seem unable to read the message - which is "I am upset". They sometimes think we are just being malicious.
So my advice would be to avoid all out final war and try to set up a training programme using more gradual rewards and punishments. Obviously you will refuse to sleep on the bed, as usual. You wouldn't get a wink of sleep anyway. Pace round it making little kitten mewing noises. Jump up on the side of your human, then shudder, crouch and hiss at the new mate beside her.
Run away immediately he comes into the house, making sure that your human sees your fear. Refuse to eat your food (you can probably get a good meal further down the street anyway). In every way treat him as if he was a cat killer. A human who smells of the vet is a killer. They call it euthanasia. I call it murder.
Sympathies,
George