Things like bathing can be very stressful for cats. If you’re using any kind of soap when you wash your cat, you could also be causing the problem by irritating the skin on his belly with soap chemicals.
A lot of people think they need to wash their cats like their dogs, but usually cats are very clean animals with meticulous grooming habits, so they’re normally able to keep themselves clean and pleasant with little help from their humans, especially if they’re strictly inside cats with short hair.
Negative re-enforcement training techniques can be stressful, too, and I hope you’re using only positive training methods.
You say your cat is sometimes grumpy. I’ve had cats my entire life and I’ve yet to meet one who isn’t sometimes grumpy. Animals have individual personalities just like their people, and cats are great because they have such a wide range of emotions and expressions. Everyone has a grumpy day sometimes, and cats can just naturally be quite aloof sometimes. So it’s a good idea to respect your cat’s cues and give him some space when he asks for it.
Cats need space when they start to flick their tails quickly, or thump them against the floor, if they’re lying down. If his ears are pointing backward, that’s another cue that he needs space, or that you’re being loud or annoying to him.Your cat in your Avatar, for example, looks very stressed and annoyed, even angry. If he starts to growl lowly, he’s really getting upset.
If he’s trying to get away from you, or using claws or mini bites that don’t break the skin but are enough to let you know he could, this is another warning to you and you need to let go and give him some time to himself.
Usually, if your cat is looking directly at you, and if his body is tense and he’s making sharp hissing or spitting sounds, that is challenge behavior and it means he thinks you have really gone too far and he’s getting ready to defend himself.
It’s just like with a person who’s had more stimulation than he/she can tolerate. You have to respect your cat’s limits.
Excessive licking which results in fur loss is pretty serious and you want to try to help your cat cope and be healthy.
I hope some of this is helpful to you and your cat. I’m sure you know all this if you’re reading a lot, but I thought I’d write it just in case.
Sincerely,
Housecat