I gave one cat a bath, just one. The bath lasted .021 seconds. It is the only cat bath I shall ever give.
I guess you could use this method.
Step 1 -- Put some Tide in the toilet.
Step 2 -- Subdue cat.
Step 3 -- Throw cat in toilet.
Step 4 -- Quickly close lid and sit on it.
Step 5 -- Wait while cat self agitates.
Step 6 -- Flush toilet for first rinse. Repeat three more times.
Step 7 -- Wait until racket stops.
Step 8 -- Have someone in MLB catchers gear ready to grab the cat when you raise the lid.
Step 9 -- Raise lid.
Step 10 -- Subdue cat.
Step 11 -- Dry cat.
Step 12 -- Prepare yourself for a wave of revenge like you've never seen.
I used to give Max the Monster Cat (25lbs, and not fat) baths regularly.
He never clawed or complained much, but afterwards he would go to the middle of the living room carpet and show me what he thought of his bath!
We had a cat like that once. Name o' Midnight, but I called him monster. Same description, but black as the devil's heart. Seriously, bulkiest and blackest cat I have ever seen, scary black. Wouldn't touch cat food, only at live prey (country cat). A real monster, but he LOVED his people. Sweetest most loving cat we ever had. In any event, I never dared to give the monster a bath, I'm quite confident he would have slashed my throat in my sleep.
Leukemia got him at about 4 years old. **** Shame. Best cat we ever had.
Get the largest caliber you can fire accurately, rapidly, in the largest gun useful for the purpose.