Cat wants to hump my arm.

Hi. My male cat who is only 8 months old has tried multiple times to hump my arm. The first time it happened I didn't know he was trying . He always attacks my arms or ankles. He doesn't go outside. He doesn't spray my house. So I didn't think about getting him fixed. Is there anything besides getting him fixed that I can do to stop this?

Getting him neutered is really what's needed here.  At 8 months old, he's coming into his horny teenage boy age and pretty soon his urine will start to smell a lot like a skunk has been in his litter box.  I always get the rescue boys neutered by the time they are six months old, if not sooner.  It makes them calmer and happier and better pets.  Most cities have low cost spay/neuter options, and your local humane society can probably tell you where to look.

Agree with the above. It's better to get him neutered before he starts spraying or getting more aggressive.

There really isn't a good way to stop this other than neutering. You'll want to do that anyhow since male cats often begin spraying or calling in the middle of the night for females, behaviors that aren't really great to have in a house pet.