Dear Britt --

There is no reason to worry but I can imagine your mortification, especially when this occurs in mixed company! It takes approximately three months for testosterone levels to decrease to insignificant levels. Neutering removes the major source of production of this hormone, but does not immediately cleanse his system of it. As the hormone level decreases the level of masturbation should decrease.

In the meantime you should remove anything that you think is acting as a stimulus for this behavior. Deleting the centerfolds of "Cat Fancy" magazine as well as removing the adorable little stuffed toy that serves as the object of his affections should help. There is a product called Fel-O-Way, which is a pheromone (hormonal) spray, that can be gently sprayed over him and his environment and will have a pacifying effect when used regularly.

One final note. I am assuming that this cat is a young adult -- under a year of age. If he is an older tomcat that has been free to wander and mate over the years, his behavior may continue to be influenced more by habit than by hormones. An oral female hormone (megesterol acetate) can be given in low doses to suppress the behavior.

Good luck!
Dr. B