Charlie cat having a seizure. He is medicated but he has had a flare up recently. If your cat ever has a seizure the first step is to make sure no other animals are nearby. Sometimes other animals will regard seizures as play or aggression and try to attack them. I rest my hand under his head so he doesn't smack his head and face into the floor or other objects(sometimes he will do so violently) or spring off his feet randomly and smack his head into a wall. Despite my hand being under his head he has never bitten me during a seizure. Even if he did I would rather be bitten than allow him to harm himself. If a cat's seizure lasts more than 5 minutes you should get them to a vet IMMEDIATELY. If your cat has a seizure 2 minutes or less you should still take them to a vet and if possible, record the incident. People often mistake other conditions for seizures (like heart attacks).

More on preventing them from harming themselves. I wouldn't hold them in my arms during a seizure. You may add additional stress. Notice the first thing I did was reach my leg and hand out as a barrier. That's not to say you can't hold them at all though. Especially if they're in a potentially dangerous environment. Or if it's dark and you aren't sure of what's around you.