|Lucy marking her cat pen to make it smell like home.|
Ever thought why we cats rub our chin and cheek against something? We are marking it with this pheromone and with our own ordinary body scent (a kind of signature mix).
If we have rubbed against our human, then that scent of human will also be there. We are making our household territory friendly by making it smell of the family - us, our humans and perhaps another resident cat (if we like him and have rubbed against him too.)
It is like a post-it note to ourselves saying "We live here: this is our home and family." Humans cannot smell this at all: nor can they usually see it.
Occasionally, if we have rubbed in the same place for a long time, our human may notice a sort of dark mark. If they are houseproud, they clean it off. This is very upsetting.
So we have to re-mark it all over again. And again.