My cat humps my bed and stuffed animals!?

Sometimes cats aren't neutered properly and that can lead to problems later on. Other times, it is purely a behavioral issue. If you don't mind that your cat needs to get his rocks off every once in awhile, let him have a good time. If it bothers you, say "no" and put an end to the behavior. If it is constant and persistent, you should pay a visit to the vet or an animal behavioral specialist.