Neutered cat biting another cat

Question
I have a male cat (Tippy) who was neutered when he was around 6 months old and had never been around an unspayed female. When he was about 1 and 1/2 we had a female (Calico) in heat and another neutered male would mate with her and bite the back of her neck at the same time. Tippy had no interest in Calico even in heat. The other male moved out a short time later and Calico was fixed. Now at 5 years old Tippy has started sitting on or standing behind Calico and biting the back of her neck but not trying to mate. Any idea why he is doing this?

Answer
Hi Stacy,
Biting the neck during mating is normal for felines. This behavior is also seen in neutered males sometimes.
Well, since he was neutered years ago it is not residual testosterone that can take some time to leave the body.
A neutered male will at times mount a female in heat as the adrenal glands still produce sex hormones.
But, since she is already spayed this could be a behavioral issue that you can work out with a cat behaviorist to resolve to modify and redirect his behavior. This behavior can be a result of boredom, lack of daily rigourous exercise and stimulation and lack of predatory expression.
Give her spaces to get away and jump onto if she is annoyed with this behavior.
Best,
Shanti