Photograph reproduced under creative commons (Flickr) copyright dave77459 - notice the black cat on the left :-) - this is not me!
A new boy cat has entered our lives here in Barnes, West London. I've called him Timmy. I don't think that he is a totally stray cat (although he might be) but he spends the day here more or less and the night somewhere else, perhaps just outside. If that is the case he may come in for the winter, we'll see.
Every morning when he walks in calling for his breakfast he rubs against my legs. And he does this more than any other cat I've met.
To me this is his morning welcoming hug before we get down to the business of eating. When cats rub against you it is partly to make friendly contact and partly to deposit on you his scent. There are scent glands by the mouth and on the temples and at the root of the tail.
When he rubs against you he leaves some scent on you. We can't smell it (because we're stupid humans :-) but cats can.
Having his scent on you makes him feel more relaxed and at home. Also he will check out our scent by sitting down after he has rubbed against you to lick the area of his body that has made contact with you, so that he can taste the scent from you.
Voila, we have a scent exchange and a metaphorical morning hug. Nice to see you Timmy, how yu doin boy. I'm a member of his cat family and I'm pleased about that. There is a lovely element of equality in that exchange in that he is approaching me and making me part of his family.