Yes, my cat likes to have sex with my left arm. You can see it in the video. I think it’s normal. I accept it completely. I want him to express his natural desires. It does no harm when he does it (except to gradually destroy my dressing gown) and I presume it satisfies him to a certain extent.
I don’t know whether anybody else has experienced this. Cats bite the nape of the neck of the female to keep her from fighting back. This is what you see in the photos.
Update: 2022: He is still doing it almost 8 years later! Every day when I wear this old dressing gown which is now thoroughly trashed ??. So winter is the time for this ritual.
Despite being neutered my cat has retained his sexual urges and his desire to procreate. He is frustrated in expressing that desire because of a lack of available female cats. He relates to me as his surrogate mother and a feline mother. When he has sex on my arm, in his mind he is having sex with his mother. This happens in the cat world.
It is a combination event. He also kneads and purrs. The kneading is a kitten response and replicates a kitten kneading at his mother’s breast to bring on the milk. He’s a bit mixed up? A lot of domestic cats are a little confused because they have wildcat instincts but live in a human environment. This creates distortions to their behavior.
The fleece dressing gown is important I believe because it feels like a cat. I have two dressing gowns and the other one does not elicit this reaction.
You can see his sex-drive in the eyes in this photo:

I think it’s important that a cat can express his natural desires and emotions as best as possible. Sometimes we have to compromise for the sake of safety and curtail these drives. Do you think I’m crazy to let him do this?

He does it while I am watching television sometimes, I just let him do it. Or when I read the newspaper. He’ll do for about 10-15 minutes, in all, which is quite a long time. At first, I stopped him but then I thought it was unfair. It doesn’t bother me. Somebody might think it’s a bit gross. Some people may think I’m wrong to allow it. As I said, I have to be wearing my fleece dressing gown which I presume feels like fur to him! He won’t do it when I am wearing other clothing.
I expect he will stop when he’s neutered (it did not change a thing by the way). He’s never sprayed anywhere (wrong: he sprays outside). He is generally a very well-behaved young cat but being young is a bit manic, driven by his instincts.
At the moment (2015) he goes out on a leash. He accepts his harness completely and likes it now. He knows that when it is put on him, he is going to go out. I’ve trained him to come to me so when he does go out alone, I am hopeful that I can call him back if I’m worried about his whereabouts.
The reason why he goes out on a leash at the moment is because I want him to become familiar with his surroundings. I wanted him to know where the door to his home is. If there is trouble, he can then race back and hide. After all, he is very young. And, of course, I would not let him free roam before being neutered. Update: I have moved home since, and he now free roams but it sensible thank God. Also being young he is liable to be stupid and do things which are dangerous to him due to inexperience.
RELATED: My cat joins me on my walk to buy the newspaper at 06:30 (video)!
I’m trying to make is life as good as possible while also making it as safe as possible. After moving home to a house he is now confined to a garden enclosure and the house.
Below are some articles on so called ‘strange cat behavior’.

Hello My neutered male cat 10 years old do the same thing. It has been almost for 3 years. Do you think they might get bacteria or infection while doing it? Thank you
My cat is neutered so can’t produce sperm. Your cat isn’t. On a practical level it makes a difference 😉 If our cats have to hump arms at least it is not messy for me! It is more likely for a cat to want to have sex if they are not neutered, I believe, but my boy wants to do it. It is only when I wear a specific dressing gown.
My 8 year old snow shoe cat does this and I don’t like it. If it were just the humping it wouldn’t be so bad, but.. If he is allowed to continue he will actually ejaculate. Does yours “finish?”😳 His big thing is anything fuzzy like blankets, but now sometimes tries to have sex with the dogs.
He never did this until someone got my a fuzzy blanket for Christmas a few years ago. We went to sleep as usual, only this time with the blanket, and he has been sexually aggressive ever since.
I don’t really agree with fixing animals or locking them away, but I would not risk surgery for him anyway because he has a heart murmur and ic which causes bladder inflammation.
Thank you so much for replying! Thank you for your kind words as well.
No, it is normal behavior really. I have replied to your other comment.
I don’t think this behavior is linked to separation anxiety. I believe it is because he regards you as his mother (cat mother) and he wants to procreate by mating with his mother. I know it is incestuous but cats can do this. To me it is a reflection of your close relationship with him. And I am pleased you accept it as I do. It is just cat behavior and I’ll bet it happens quite a lot but most people don’t talk about it 🙂 Thanks for sharing.